I am having the same issue with emailing clients copies of their 2022 return.  I use Thunderbird and have always been able to email with that.  I can still do from 2021, just not 2022.  Was on phone with tech pros 3 times and final solution suggestion was to uninstall Thunderbird and purchase Microsoft Outlook 365.  I can do that, but still have a problem with purchasing a subscription that will continue into the future when it seems to be a problem for Proseries to correct.  I pay a lot for the service, and have for many years ( since before 2013).