How did you "connect to" the shared folder? Did you open it from Windows Explorer directly?
Besides, if you open the folder from OneDrive online, can you edit files in this shared folder?
It's best to let the owner check your permission on this OneDrive folder.
- If condition permits, let admin, run following diagnostics within the tenant in Microsoft 365 Admin Center to identify possible issues. https://aka.ms/PillarCheckUserAccess
- Let owner go to OneDrive online > In the upper right corner, click "Settings" > “OneDrive Settings” > In the upper left corner, click “Return to classic OneDrive" > Find and right-click on the shared folder > Share > Shared with. Ensure you have enough permission to access this folder.
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