How to set up mail through Google Apps so that letters do not fall into the addressee's spam?

Question

Google Workspace

Good afternoon,
All my mail is stored on Google Apps. Set up MX records at the host to redirect mail from my domain to Gmail (Google Apps).

v=spf1 a mx a:mydomain ip4:myserver ip include:aspmx.googlemail.com ~all

• At the same time, the IP of my server is "clean" and is not highlighted in the black lists.
  
• The external IP of my provider is blacklisted (probably one of the provider's clients spammed)
  In TheBat's SMTP settings! smtp.gmail.com specified (authenticated on port 567)
  

The problem is that the mail does not reach the addressee, because. his mail server somehow determines that mail was sent from my ISP's External IP .
How is my provider's External IP translated to the final destination if my domain and server are "not exposed" and how can I solve this problem? Can I correct the SPF record on the server?

Answer 1

Yet blacklists are the problem of the one who receives the mail. In your case, only the tunnel outward will save if the recipient's mail server (more precisely, the admin of this server) is so stupid that it checks all hosts in the Received: chain. By the way, I would not believe that he has a well-configured spf and dkim checker.