Welcome to the forum @HellFok
Duplicati cannot finish archiving has some general troubleshooting information, however your situation seems different because you have extra files instead of missing ones. Are you trying to manually delete backup database .sqlite file? If you do that you also need to delete the remote files, or they’ll be “extra”, compared to the local DB record, and can cause the message you got. What other steps led up to this?
Are you using WebDAV? I don’t think anything else is available, and Yandex WebDAV is having trouble.