Cannot send email to gmail

Please a help. The vps server cannot send email to gmail. What should I do?

mail2

What is email score from here ? Test Email Score - CyberPanel on Cloud

it gives an error, the test does not start

refresh page and try again.

I have these problems

Yes please add DKIM and set rDNS.

Can you tell me how to solve these dns problems?

Please check this: Achieve 10/10 Email score with CyberPanel!