Go to the Configuration page of your backup profile.
Find the Post-processing engine row.
Change it to “Upload to Microsoft OneDrive or OneDrive for Business” — this one uses the more modern API for communicating to OneDrive. You are currently using the legacy “Upload to Microsoft OneDrive (LEGACY)” which uses an old API with very strict limitations.
Click on the Configure button next to it.
You will have to re-authenticate to OneDrive; the new API authenticates you with OAuth2.
After you are done with the authentication and you have copied over the tokens to Akeeba Backup per the on-screen instructions please make sure that the “Enable chunk upload” option is checked. This allows Akeeba Backup to upload big backup archives in small chunks and ask the OneDrive API to “stitch” them together.
Finally click on Save & Close.
Nicholas K. Dionysopoulos
Lead Developer and Director
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