How to fix android.defaultConfig.versionCode is set to -1, but it should be +ve error

Yes, 1.5.11 is currently beta software. Google didn’t review this version yet but it will be in the Playstore beta channel soon.

If you are talking about Dropbox and Onedrive: You have to provide API keys to access this cloud services. In case of Dropbox, also have a look into this issue: Cannot authenticate inside Dropbox · Issue #242 · cryptomator/android · GitHub