As it is said, stablebit cloud drive is not that stable.
I went into troubles uploading files sometimes, of course it's not stablebit's fault. However, the auto retry seems to be useless. Each time I have to close the app, restart the stablebit cloud drive service manually, and open the app again, and that is fixed, temporarily. It's complex and it takes a lot of time. I think that add a restart button can compensate for it in some aspects.