Why can't gmail see s/mime?

Question

gmail

Created mail by type: [email protected]
Incoming and outgoing connections use SSL.
I also bought a certificate (signature) for email. Installed and a tick appeared.
I am using Apple Mail client. After installing the certificate, the letters no longer end up in spam (but when you write to this address, they go to my spam). Also, when sending a letter to gmail, a note appears in the letter: "The digital signature is not valid"
It is also indicated that TLS encryption is used, does this somehow affect the fact that I have SSL installed.
Why is the certificate in gmail not valid and how to fix it?
Thank you!

Answer 1

You need to start with "Created mail by type: [email protected]"
Not enough details. Where was it created and how?
S / MIME has nothing to do with it, Google swears at the TLS of your mail server.