I encountered a problem with Dropbox Backup plugin (free version): every time I run backup, I receive error message about file locks:
Dropbox Backup wasn’t created. Dropbox returned an error during file sending: “Failed to grab locks for 1383594705: lock held by connection 13273987. Please re-issue the request.”
Plugin screen shows the error message in big, red letters, and uplaod progress bar stops in the mid-way:
You has started two backups simultaneously. If it happen – don’t panic. Just wait until started backup processes will be finished or interrupted.
And this error is an answer from Dropbox system about simultaneous query’s.
Explanation of this error message:
The “Failed to grab locks for” message indicates a technical inability to make the state modification in the account at the time of the API call. This error generally indicates that there was simultaneous activity in the account preventing your app from making the state-modifying call (e.g., adding, copying, or removing files) it is attempting. The simultaneous activity could be coming from your app itself, or elsewhere, e.g., from the user’s desktop client. The best practice when receiving this is to just retry the request, respecting the `Retry-After header if given, or after a small delay possibly with an exponential back-off. If the activity is coming from your own app, you should avoid making multiple state-modifying calls in the same account at the same time.
The same explanation you can read on dropbox support forum: https://www.dropboxforum.com/hc/en-us/community/posts/204555365-Failed-to-grab-locks