Not receiving emails

Your mail has stopped working

either due to the fact that the ssl certificate has expired, or the imap / smtp data is not correct, which is what the error says
mail.adm.tools,993

The certificate is valid until 03/23/2021.
Access is correct. For the following reasons:
1. I rechecked.
2. Previously, letters came with the same accesses, then they stopped.
3. Letters with these accesses are sent
Are there any other options why the error might occur?

now the problem is in smtp, this is what needs to be checked.
For the server to work imap / smtp and the data is correct

why do you need to check smtp if there is an error in imap on your screen?)
Access is unambiguously correct. Are there any other options why the connection to the mail server might fail?

let's do it)
1. From the CRM side - everything works stably, all connections are there - everything is ok
2. From the side of the server to which we are addressing for mail parsing - there are errors. Some mailers respond, and some mailers do not.
My recommendation is this
1. For the time being, disable mails that do not work (12 hours), at least. To exclude the option that the ip address was somehow banned (this sometimes happens)
2. Reconnect mail in the morning
3. If the error persists, you need to write to the support of the mail aggregator :)

Turned off yesterday and turned on today. What do I need to write to mail server support?

Here is the answer from those. server support
Here are the results of the traceroute query

Please comment on the mail server support response. Is there anything else I need to do?