Emails that include a specific office number sent from GoDaddy Office 365 are being flagged by Gmail as SPAM.
When I send emails that do not include this specific office number, emails are delivered to the Gmail users Inbox. When the body or email signature includes the extension 8305, gmail will deliver the email to the SPAM folder. I have tried all different variations, including bracketx, dots, hyphens, spaces, etc... when you add the entire number, the email is sent to the Gmail SPAM folder. I have even swapped out the numbers, and the email is delivered perfectly. Its only with the 8305 extension is added to the email, that gmail decides to filter and deliver the mail to the SPAM folder.
Also, when I test and send the exact email from my on-prem Exchange 2010 box, the email is delivered properly to the gmail Inbox. I was leaning more towards Google being the issue, but it seems to be GoDaddy Office related. What exactly should I be looking for? In my research, I see posts to ensure that my SPF and DKIM are setup properly. I have checked MXtoolBox and everything comes back OK. Not sure what else to check? Any suggestions?