Hello KOSulli1
It could be timing out to the server when trying to access the server. What you will be able to do is extend the timeout extender for AccountRight which I have linked to our post with steps on how to do so.
If still having the error pop up after extending the timeout extender. What you will need to do is take a backup of the company file and restore the backup locally so that the file isn't online. You should then be able to access the print/email invoices. After accessing it and printing and emailing the invoices, you should be able to restore that file online and this should resolve the error popping up.
I have linked our Help Article on backing up and restoring company files which give details on how to restore locally.