We have recently added some new email sending domains to our SalesForce Marketing Cloud account - I have had confirmation that this have been configured correctly. Some of these new domains end with .properties, .site or .website and the rest in more common .co.uk

The domains which end .co.uk are delivering fine into Gmail but the ones that end in .properties, .site or .website are having all traffic rejected with a bounce type of "Content". We have conducted testing where we have used the same HTML and sent to the same people using a sending domain ending in .co.uk and it delivers fine, but when we send using the other ones they bounce back.

The IPs are established & have sufficnent mailing history. Does anyone know if the new tld domains are not accepted by Gmail for email marketing activities? Or is anyone using these TLDS successfully?