Failed while executing "Backup" with id: 23

[warwickmm]

I think this is the same issue as here:

110 canary, multiple sources not supported (?)

This is likely the problem. Supporting the Tardigrade and TencentCOS backends (which are built on .NET Standard) required us to move to .NET 4.7.1 (and hence Mono 5.10.0 or greater). However, it seems that there is an issue with mono packaging in Debian-based distributions: This also causes a problem with our official Docker image: So far, it seems the solution is to install mono-complete, or the equivalent.