I dont know why all my website receive message on gmail spam?

Hi, I don’t know why all my websites receive messages on Gmail spam? Can someone help me sort out this issue?
Thanks in advance

check using google header analize and mxtoolbox analize

1. dkim
2. spf
3. domainkey
4. ssl
5. server IP
6. domain name
7. add to postmaster google

check your IP here Email Blacklist Check - IP Blacklist Check - See if your server is blacklisted
also, show the result of https://www.mail-tester.com/

Thank you for your message, may I know how I can do that?

This is what i get, please see attached, what should i do? thanks

Screenshot_81573×1019 176 KB

Click on those yellow tick boxes and there it will mention the solution too.

Secondly check if your server ip is blacklisted : Email Blacklist Check - IP Blacklist Check - See if your server is blacklisted