Universal SPF is presented as a layer 2 extension designed to address broken SPF policies and improve email deliverability by circumventing limitations of the existing SPF protocol, especially the 10 DNS lookup limit. Common SPF errors such as exceeding DNS lookup limits, syntax errors, and incorrect use of 'include' statements can cause 'permerror' results, leading to hard fails. Universal SPF aims to signal receiving servers to allow these policies to still pass or fail as intended, while techniques like SPF flattening can also reduce DNS lookups. However, it's important to note that Universal SPF isn't an officially recognized IETF extension, and the term 'extension' may be misleading. The original SPF was designed to mitigate DOS attacks, and correct configuration is critical to avoid deliverability issues.