Our Xeams host is directly connected to the internet - it's in a public cloud.  There's no firewall handling of SMTP.  I was able to successfully test with the email sender tool.  The certificates presented look normal.  

SSL Certificate for: gmail.com
Issued by: CN=GTS CA 1C3,O=Google Trust Services LLC,C=US, valid until: Mon May 20 04:18:12 EDT 2024, Host: CN=mx.google.com
Issued by: CN=GTS Root R1,O=Google Trust Services LLC,C=US, valid until: Wed Sep 29 20:00:42 EDT 2027, Host: CN=GTS CA 1C3,O=Google Trust Services LLC,C=US
Issued by: CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE, valid until: Thu Jan 27 19:00:42 EST 2028, Host: CN=GTS Root R1,O=Google Trust Services LLC,C=US
Total certificates: 3

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SSL Certificate for: gmail.com
Issued by: CN=GTS CA 1C3,O=Google Trust Services LLC,C=US, valid until: Mon May 20 04:18:12 EDT 2024, Host: CN=mx.google.com
Issued by: CN=GTS Root R1,O=Google Trust Services LLC,C=US, valid until: Wed Sep 29 20:00:42 EDT 2027, Host: CN=GTS CA 1C3,O=Google Trust Services LLC,C=US
Issued by: CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE, valid until: Thu Jan 27 19:00:42 EST 2028, Host: CN=GTS Root R1,O=Google Trust Services LLC,C=US
Total certificates: 3

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