Hello @starkita and welcome to the forum!
The “X files not found in remote storage, please run repair!” message indicates that a bunch of files that Duplicati expected to find at the destination weren’t found.
Since Duplicati has to ask the destination for a list of files to compare to the local list, if the list isn’t returned or is only partially returned Duplicati will think files are missing from the destination.
If this happens with every run, then the files may actually be missing and you should click on one of the errors in your job log to get the specific file name then manually look on your destination for that file.
If it’s NOT there, then there’s not much that can be done - the file is gone.
However, if it IS there then the issue is most likely that Duplicati can’t see it for some reason. This might be due to a permissions problem (again, if this happens every run) or it could be a general internet glitch (if this only happens sometimes).
Also of note is if it’s the same files listed each time the error happens. If not, then it could be a destination problem (in the past there have been issues with file lists coming from some providers being incomplete or even having duplicate listings).