Hi Roman,
Nice to meet you here.
Thanks the logs you attached, I found there are many connection timeout errors during backup process. This issue maybe related to the port connection, Vinchin needs to connect DB server 22710 & 22711 while backup, please check if these ports are connectable from Vinchin to DB server.
Besides the port issue, if there is any firewall rules or flow control equipment between Vinchin and DB server, please also allow this transit during backup process.
Here are some related resource of this DB Backup module, maybe helpful if this is the first time testing Vinchin, please check:
https://helpcenter.vinchin.com/docs/db-backup-restore/mssql-server-backup-restore.html
https://www.vinchin.com/how-to-video.html
Looking forward your feedback.