You cannot change an account in TB from one to the other. To switch, create an IMAP account alongside the POP account. If those messages are no longer on line, you can save them by moving the message folders to Mail\local folders (when TB is NOT running). If you want to view those messages from other points, you can upload to the IMAP folders, but that is problematic. I suggest uploading only a few at a time, as that is not a strength of IMAP.

Thanks, David, for this disappointing information. I do not understand, however, what you mean by creating an IMAP account alongside the POP account. That makes no sense to me. Nor does the following sentence about moving message folders to Mail\local folders and how to do that when TB is NOT running. How will I see all the messages I have in the many client folders I have set up (I'm a CPA)? I am pretty much lost with all this, being a person of a certain age and different areas of expertise. Thanks for any help. Margaret

I do not mean to confuse. My concern was that, if you delete the POP account before setting up an IMAP account, messages you may have saved on your PC that are no longer on the server could be lost. That was why I suggested moving any messages in the POP account to Local Folders so that they would still appear after deleting the POP account. Since Thunderbird can have multiple accounts at the same time, you could create a new account with IMAP without deleting the POP account. Thunderbird treats all accounts independently. Yes, once in IMAP, you could read, compose, and reply from your phone or other PCs.

Thanks for your quick reply! I've done some more reading, sadly not more understanding. However I did find that if one sets up another account (IMAP), the instructions say to change the email address or at least to not delete the POP account without deleting the email address. Well, I've had my business email address for about 25 years and cannot so easily change it. So I am just baffled how/why, after years of using TB with the current setup, it suddenly changed. I was out of town for a week and everything blew up. I only see mass confusion if I have both a POP account to receive email and an IMAP account to send email (how does one reply to a client who sends a message to the POP email account and have to reply from an IMAP account with a different email address?). As I wrote to my hosting service, very responsive but not TB folks, I could just cry now. Any other advice? Margaret

You do not need a different email account. Thunderbird treats all accounts independently. If you do not need the POP account, just delete it. You do NOT need both as that could be confusing. Even if you kept both, you could read and respond on either one. Customers would not know or see any differences. You are the one who will get confused if you use both. If you want to use IMAP, my approach would be: - set up the IMAP account for ongoing business - review POP account to be sure you have it set to leave messages on server - review the messages in POP message folders. Are there any that are not online? Probably. Create a safe haven for them in local folders. You can still reply from local folders. - Once all reviewed, you can delete the POP account

Let's pause. You stated that your account was changed. Is it worth pursuing this? If you're having a problem, we should explore that. So far, we've been discussing switching from POP to IMAP.

Thanks so much! I have to go now to a meeting but this has been so helpful. I do need to reread and digest and have a couple more questions but it will have to wait. Thanks again!

Hello again, I'm back but will have to continue tomorrow late afternoon or Wednesday due to other commitments. I hope you are able and willing to guide me. When I said the account was changed, all I know is that the day before I left on Jan. 20, I was able to send messages and, so far as I know, the 3 accounts on my website server host were set up as POP accounts as directed a few years ago. My gmail account was set up, per directions, a few months ago, as IMAP. On my return yesterday, I could no longer send messages from any accounts through TB. The host folks sent me information for the SMTP settings and IMAP incoming server settings. But when I looked at incoming, I saw that each (except gmail) was POP Mail Server. And the port is wrong - I guess. I did not make any changes. I don't know if my host server changed something, TB changed something or what. It worked Jan. 19 and did not work Jan. 28 and I did nothing in between.

Apparently my web host now says incoming must be IMAP so I began looking into how to change it - which apparently I cannot - easily. From your help and their KB (form 2020 for Mozilla/Thunderbird), it seems I can only add another IMAP account and hope and pray for the best. Just as tax season has begun and I need to communicate with my clients. Sigh...

Here is the message I was getting: Send Message Error: Sending of the message failed. An error occurred while sending mail. The mail server responded: SMTP AUTH is required for message submission on port 587. Please check the message recipient "anyone I sent to" and try again. The host support said this: Please ensure that you are using the following settings for the email accounts in your email client:

Outgoing server SMTP Host: nanj1.armadaservers.com SMTP Port: 465 ( SSL ) / 25 (NO-SSL)

Incoming server IMAP Host: nanj1.armadaservers.com IMAP Port: 993 ( SSL ) / 143 (NO-SSL)

So I did change the SMTP port to 465 as it was 587 on those email accounts on that server. And now I can send a message from one specific account to another specific account but not all. Kind of making me crazy. I think I mentioned before, I could cry. Thanks again for your help. Margaret

Margaret, What they told you contradicts their own instructions at https://www.hostarmada.com/tutorials/getting-started/email/how-to-setup-an-email-account-in-mozilla-thunderbird/

That is, the SMTP server should specifiy STARTTLS and port 587. The incoming should specify SSL/TLS and port 993

Their site also indicates that POP is an option.

That 'SMTP AUTH' error message is because you do not have STARTTLS specified. The email host gave wrong advice in specifying to use no authentication.

I am concerned that your original problem may have been only a minor item to fix and that it has seemingly forced you to IMAP. I guess that is history now. BUT, if you wish to stay with POP, that seems okay, but you also indicated you want access from other devices, such as phone or other PC. Please confirm which direction you want to go.

Thank you yet again for continuing to help me. I have to go to a client office just now so will have to deal with this later. I think I understand what you wrote and have not changed to or added an IMAP account (except for my gmail account). To avoid confusion and messing up 20+ years of work with Eudora/TB, I really would rather stay with POP until I retire in 2 1/2 years. I have TB only on my main business computer so do not access on my phone or other PC via TB, just directly. I will get back to this later. Thanks again! Margaret

I concur. If it ain't broke, don't fix it. If you need assistance, let us know. I hope you are doing periodic backups when Thunderbird is not running.

Well, an astonishing thing happened. I was out all day yesterday. When I returned and tried things again, everything worked fine. I just now checked settings again and SMTP is set at 465 (TB says default) and SSL/TLS and the incoming for all POP 3 accounts is the server as identified by the host server folks, Port 110, default; Connection security None, Authentication method Password, transmitted insecurely (no idea what these mean).

For my gmail acccount, IMAP, it is Port 993. SSL/TLS, OAuth2 (no idea what these mean).

It all seems to work now although I really don't know why. If you have suggestions about what to change, I may try but revert to these settings if anything gets messed up again.

Super thank you for sticking with me on this and for being so knowledgeable and willing to share!