I found finally where was the problem

In the events the system told to me that it could't find the database

Today, I've remembered that I've excluded all exchange databases from provisioning with the next command

Get-MailboxDatabase | Set-MailboxDatabase -IsExcludedFromProvisioning:$true

After that, I included a database for proviosioning

Get-MailboxDatabase <database> | Set-MailboxDatabase -IsExcludedFromProvisioning:$false

The database I set up, was the database that is created when you install Exchange

I tried to change the exclusion to other database and now it's working fine

Glad you figured it out.

This can indeed happen sometimes (normally if hdd was full or similar it tends to exclude db's for example)