If you find that emails stop working in Prodoc, this can be the result of a previous email item blocking the queue and is usually caused by an application accessing the file before Prodoc can send it to Outlook via a SimpleMAPI connection, such as an antivirus scanning the file and locking it.
Copy and paste these into your address bar as pictured:
%LocalAppData%\Prodoc Ltd\Prodoc\Prodoc Outlook Emails
%AppData%\Prodoc Ltd\Prodoc\Prodoc Outlook Emails
%LocalAppData%\Prodoc Ltd\Prodoc\Prodoc Emails
%AppData%\Prodoc Ltd\Prodoc\Prodoc Emails
Delete everything you find in these folders.
Don’t worry if any of them don’t work, just move on.
If you can’t delete a file, close the application that says has locked it (this will be the reason it couldn’t send initially, sometimes Antivirus can get in and lock it before Prodoc can, then it’s all downhill from there). Might need to log off and on again to close it.
If there are no files to delete, then get in contact with Prodoc Support, likely there’s another reason it’s unable to make the connection.