My SendGrid emails show 'delivered' but don't arrive in Gmail inboxes. Why?

This usually indicates the receiving server accepted the email but then filtered it into a spam folder, a promotions tab, or quarantined it. SendGrid's 'delivered' status only confirms the hand-off, not inbox placement.

Are there specific Gmail filtering rules for Vietnam that could be affecting my deliverability?

Gmail uses advanced filters that consider language, sender reputation, content quality, and historical engagement. Specific issues can arise if your content is not properly localized for Vietnamese recipients, or if your sender reputation (especially on a shared IP ) is low in the region.

What technical checks should I perform if my SendGrid emails aren't reaching Gmail in Vietnam?

Ensure your SPF, DKIM, and DMARC records are correctly configured and aligned. Use Google Postmaster Tools to monitor your sender reputation and spam rates. Additionally, verify your email content is in Vietnamese and correctly encoded ( UTF-8 ) for optimal display and to avoid spam triggers.

What if the issue is with a G Suite business domain rather than a personal Gmail account?

If recipients are using G Suite for business, their organization's IT administrator should check their internal mail logs, quarantine, or spam folders. Business accounts often have additional filtering layers or routing rules that can impact email delivery, even for legitimate senders.

Why are my Sendgrid emails to Vietnam not reaching Gmail inboxes? - Troubleshooting - Email deliverability - Knowledge base

Dealing with SendGrid emails not reaching Gmail inboxes, especially for recipients in a specific country like Vietnam, can be a complex and frustrating issue. It's common to see messages marked as 'delivered' by your email service provider (ESP), like

SendGrid, only for them to vanish before hitting the intended inbox. This discrepancy usually indicates that the receiving server (in this case,

Gmail) has accepted the email but then filtered it into a spam folder, promotions tab, or even quarantined it entirely.

When deliverability issues are localized, as you're experiencing with Vietnam, it points towards specific filtering rules or reputation factors that are regional in nature. While your setup might be fine for other countries,

Google and other ISPs often employ different algorithms or stricter policies for certain regions or languages based on observed spam patterns.

This guide will walk you through the potential reasons your SendGrid emails are facing deliverability challenges to Gmail in Vietnam and what steps you can take to diagnose and resolve them. We'll look into technical configurations, content best practices, and regional considerations that impact inbox placement.

Understanding localized email deliverability

When emails are reported as 'delivered' but don't show up in the inbox, it typically means they were accepted by the recipient's mail server, but then got filtered. This delivered, but not appearing in inbox scenario is a classic indicator of advanced spam filtering or internal routing rules on the recipient's side. Gmail, in particular, uses sophisticated algorithms that consider many factors beyond basic authentication.

One significant factor is language. If your emails are in Vietnamese, and Gmail's filtering for that region or language detects unusual patterns, it might increase the likelihood of them being flagged. This could be due to known spam tactics associated with certain linguistic characteristics or content that is common in that region. Even if the content is legitimate, unusual formatting or specific keywords could trigger filters.

For business domains using G Suite, the problem might not be with Gmail's consumer filters but rather with internal company-specific mail routing or security policies. If the recipients are employees within a company, their

G Suite administrator might need to check the mail logs or quarantine settings to see where the emails are ending up. It is worth investigating why Gmail is sending mail to spam folders in this context.

Essential email authentication standards

Even if your SPF and DKIM records are technically 'validated' for SendGrid, subtle issues can still impact deliverability, especially with strict receivers like Gmail. SPF (Sender Policy Framework) ensures that your domain authorizes SendGrid's servers to send email on its behalf. DKIM (DomainKeys Identified Mail) provides a digital signature, verifying the email hasn't been tampered with in transit.

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is the third critical authentication standard. It builds upon SPF and DKIM, giving domain owners the ability to tell receiving mail servers how to handle emails that fail authentication (e.g., quarantine or reject). Without a properly configured DMARC policy, or if SPF/DKIM alignment fails, even legitimate emails can be treated as suspicious, leading to them being flagged as spam. This can be a reason Gmail rejects unauthenticated email.

Another technical aspect to consider, particularly for non-English languages, is email encoding. Ensure your email content and headers are correctly encoded, typically using UTF-8, to properly display Vietnamese characters. Incorrect encoding can corrupt the message, making it look suspicious to spam filters. Test your email's display across various clients to confirm it renders as expected.

Example SPF record for SendGriddns

v=spf1 include:sendgrid.net ~all

Sender reputation and content quality

Even with perfect authentication, sender reputation is paramount. If you're using SendGrid's shared IP pools, your reputation is influenced by other users on those IPs. If some users are sending spam or have poor sending practices, it can negatively affect your deliverability, especially to ISPs with strict filtering. A common reason for emails going to spam is if too many users are reporting emails as spam.

The content of your email also plays a crucial role. Generic spam triggers, like excessive capitalization, exclamation marks, suspicious links, or certain keywords, can lead to filtering. This applies universally, but localized nuances can make a difference. Ensure your email content is clear, concise, and provides real value to the recipient. Always include a clear unsubscribe link, as this is a fundamental requirement for good email hygiene and helps maintain your sender reputation.

For specific issues like transactional emails from SendGrid being flagged as spam, consider the advice outlined in the Twilio blog. If open rates are consistently low only for Vietnamese recipients, it suggests that Gmail's filtering mechanisms are particularly sensitive to your sending patterns or content when targeting this region.

Content best practices

Relevance and value: Ensure your content is highly relevant to your audience and provides clear value, avoiding generic marketing jargon.
Clean formatting: Avoid overly complex HTML, excessive images, or suspicious-looking links that might trigger spam filters.
Clear sender: Use a recognizable and consistent 'From' name and email address that recipients trust.
Unsubscribe options: Always include a clear and easy-to-find unsubscribe link in every email.

Advanced diagnostics and monitoring

To effectively troubleshoot these issues, you need deep insights into how Gmail views your sending. Google Postmaster Tools is an indispensable free resource. It provides data on your domain's reputation, spam rates, IP reputation, and authentication errors (SPF, DKIM, DMARC), specifically from Gmail's perspective. Analyzing these dashboards can pinpoint if Gmail is flagging your emails due to perceived spam or authentication failures.

Another crucial step is monitoring your domain and IP for blocklists (also known as blacklists). While SendGrid manages its own IPs, if your domain or a shared IP lands on a reputable blocklist, it can severely impact deliverability across all ISPs, including Gmail, especially in regions with sensitive filtering. Even if SendGrid's status indicates 'delivered,' a blocklist entry could cause the recipient server to silently drop or quarantine the email.

If you're sending to G Suite domains (business accounts), it's important to differentiate between general Gmail consumer filtering and enterprise-level filters. Business domains often have additional security layers, internal routing rules, or third-party spam filters that can override standard Gmail inboxing. Collaboration with the recipient's IT team or Google Workspace admin is crucial in these cases.

Common issues

Generic content: Emails lacking personalization or appearing as bulk send.
Shared IP reputation: Negative impact from other SendGrid users on your shared IP.
Locale mismatch: Discrepancy between sender's perceived location/language and recipient's.

Solutions and actions

Personalization: Segment lists and tailor content. Use dynamic fields for recipient names.
Dedicated IP: Consider a dedicated IP with SendGrid for full control over your sending reputation.
Localized content: Ensure emails are well-translated and culturally appropriate for Vietnamese recipients.

Factor	Impact on deliverability	Action to take
Language filtering	Gmail may flag content not matching recipient's primary language.	Translate emails accurately to Vietnamese and set correct character encoding.
Local domain	A Vietnamese domain (.vn) helps with regional trust.	Ensure your sending domain is appropriate for the target audience.
Engagement metrics	Low open rates and high spam complaints worsen sender reputation.	Segment your list, send to engaged users, and monitor Postmaster Tools.

Views from the trenches

Best practices

Segment your audience precisely: Send highly targeted emails to active Vietnamese subscribers to improve engagement rates.

Test email rendering and content: Use an email deliverability testing tool to preview how your emails appear in Gmail inboxes, specifically for Vietnamese characters and formatting.

Monitor Gmail Postmaster Tools regularly: Pay close attention to your domain and IP reputation, spam rates, and delivery errors for insights specific to Gmail.

Common pitfalls

Ignoring local market nuances: Applying a global sending strategy without adapting to specific country or regional filtering tendencies.

Assuming 'delivered' means 'inbox': Misinterpreting ESP delivery reports as successful inbox placement without verifying with actual recipients.

Overlooking DMARC: Failing to implement or correctly configure DMARC, which is critical for consistent authentication and sender trust.

Expert tips

Consider a local IP if volume justifies it, as this can sometimes improve regional trust signals. However, this is a significant investment and requires careful warming.

Engage directly with a small group of Vietnamese recipients to understand where emails are landing and if any internal rules are at play.

If using a shared IP, consistently maintaining very high engagement rates and low spam complaints can help mitigate the risks associated with other senders.

Marketer view

Marketer from Email Geeks says that they've noticed delivered messages not appearing in the inbox, similar to issues with Microsoft domains, indicating that the email might be quarantined by the receiving server's filters despite being accepted.

2021-08-11 - Email Geeks

Expert view

Expert from Email Geeks says that Gmail does filter based on language, so if emails are sent in a language that recipients do not regularly speak or receive mail in, it is more likely for those emails to go to spam.

2021-08-12 - Email Geeks

Key takeaways for deliverability

Resolving SendGrid email deliverability issues to Gmail in Vietnam requires a multi-faceted approach. It's rarely a single problem but rather a combination of technical, content, and reputation factors, compounded by regional filtering nuances. You need to ensure your email authentication (SPF, DKIM, DMARC) is impeccable, as this forms the bedrock of trust with ISPs.

Beyond technical setup, content quality and sender reputation are critical. Sending valuable, relevant, and properly formatted emails, especially in the local language, significantly boosts your chances of inbox placement. Leveraging tools like

Google Postmaster Tools and continuous monitoring for blacklists will provide the data needed to make informed adjustments.

Persistent monitoring, A/B testing variations in content, and adapting to feedback will be key to improving your deliverability. By systematically addressing these areas, you can significantly improve your SendGrid emails' chances of reaching Gmail inboxes in Vietnam and beyond.