In Acrobat, go to Acrobat Pro > About Adobe Acrobat Pro. Check if Acrobat is updated to version 21.005.20058 or later. If not, go to Help > Check for updates.
On macOS, when you share a PDF for review by hosting it on SharePoint, the comments don't sync.
The issue occurs when the corresponding SharePoint entry in the Keychain Access application is corrupt and unable to correctly authenticate your access credentials. Do the following: