When backing up a network shared folder you get 'The credentials for network share are incorrect' error, even though you are able to access this share in Windows File Explorer using the same credentials.
Issue in the product caused by 'File-level backup snapshot' being enabled in the backup plan options. The agent tries to access network share without credentials if file-level snapshot is enabled.
Acronis development team is working on the issue. However, file-level snapshot is not effective for network shares, thus it is safe to disable it: