SMTP error codes
Mail servers produce Simple Mail Transfer Protocol (SMTP) codes in response to transaction requests. Some of these response codes indicate errors.
You may see the following errors:
| Error code | Description | 
|---|---|
| XGEMAIL_0001 | Message didn't contain a valid DKIM signature. | 
| XGEMAIL_0002 | Message failed an SPF check. | 
| XGEMAIL_0003 | Message failed a DMARC check. | 
| XGEMAIL_0004 | Sender IP address failed an RBL test. | 
| XGEMAIL_0005 | Sender domain failed a DBL test. | 
| XGEMAIL_0006 | Message rejected because the TLS version used doesn't match the version configured in your policy. | 
| XGEMAIL_0007 | Message rejected because your license has expired. | 
| XGEMAIL_0008 | Message rejected because a domain, an IP address, or an email address is in the admin block list. | 
| XGEMAIL_0009 | Message rejected because a domain, an IP address, or an email address is in the user block list. | 
| XGEMAIL_0010 | Message rejected because the recipient's domain isn't a Sophos Email protected domain. | 
| XGEMAIL_0011 | Message rejected because the recipient's email address doesn't exist in the Sophos Email protected domain. | 
| XGEMAIL_0012 | Message rejected because it exceeded the allowed size. | 
| XGEMAIL_0013 | Message rejected because it exceeded the maximum number of recipients allowed for a large message. | 
| XGEMAIL_0014 | Message rejected because it exceeded the recipient's inbound rate limit for the single sender. | 
| XGEMAIL_0015 | Message rejected because it exceeded the recipient's total inbound rate limit from all senders. |