To get better assistance, please clarify the details. For example, are you unable to send mail with either one, or is just one the problem? Posting screenshot of error message and one of the SMTP server settings pane may prove helpful. Thank you.

Thank you for the response. I use the Thunderbird app on my phone to manage email through my Porkbun domain. I receive all email just fine with the app. However, if I reply to an email, it appears on the app to have been sent but nothing is received on the other side. There is no error notification. I've tested this by sending my self an email from a gmail account. Then I reply to the email and I never receive the reply. If I do the same activity using Outlook on my desktop all email is sent and received. So, it seems like there is something going on with the Thunderbird app, possibly in settings, but I can't find it.

Thank you for your help.

Jeff

First, I do not use the Thunderbird smartphone app, so I cannot give any detail suggestions. But I do suggest monitoring activity from your online account to see what is actually happening. Also, if you have a PC, I suggest setting up the account on Thunderbird there to see if the results are the same. That may assist in narrowing down the issue. I did locate what may be the settings at

https://kb.porkbun.com/article/146-email-client-configuration-settings