What's wrong with the mail server?

Question

Exim

I observe entries in the logs by type:

'адрес сервера' R=dnslookup T=remote_smtp: all hosts for 'адрес.сервера' have been failing for a long time (and retry time not reached)

Google says to clean up /var/spool/exim
But, doesn't this entry say it can't connect to this 'server address'?
Tell me what this log means, how to avoid this in the future?
Is it possible that the hoster simply closed some port like the 25th and letters do not reach this address? (It reaches others)

Answer 1

There is nothing wrong with the record. It is normal behavior for Exim to periodically run through the queue and try to send mail from it.
And there can be a lot of reasons: crookedly configured graylisting on the recipient, crookedly configured resend intervals, incorrect entry in DNS, your DNS is blunt, the recipient's server is corny dead, you are in some rare blacklist, storms on Mars, the recipient's server ( or sender) set up a kote and it has paws (=
Look for the first bounce messages at this address, maybe it will become clearer.
The easiest option is to try to write to this address from some popular mail service like google or yandex. If the letter does not reach, then the problem is clearly not on your part, and if it does, then it may be possible to communicate with the administrator and find out what is wrong.

Google says to clean up /var/spool/exim

Exim has tools to specifically remove problematic messages from the queue without such barbaric tricks. How many messages do you have in the queue ( exim -bpc )?

Is it possible that the hoster simply closed some port like the 25th and letters do not reach this address? (It reaches others)

Extremely unlikely.