Any Mozilla Thunderbird experts out there?

[Kimist]

I am a long-time user of both Mozilla Firefox and Thunderbird. Recently I had to uninstall/reinstall my antivirus software. Everything went reasonably well.
However, I can no longer click on the email button ("attach to email") from within the Adobe PDF viewer screen, as I've done in the past. (I can now only SAVE the pdf file, and then separately attach it to an outgoing email.)
When I try to attach/send from within the Adobe viewer, I get an error message of the type "Server connection error...please verify that port 993 is available for connection..."

It appears that Thunderbird is currently configured for POP, but IMAP may now be needed for operation using Adobe functions.
I have the instructions to set up an IMAP account ( https://www.fastcomet.com/tutorials/...rbird-imap-ssl ), but I'm reluctant to do so at this time. My concern is I would have an "old" (POP) set of emails and a "new" (IMAP) set of emails. **IF** that is the case, I would likely defer to keeping my Thunderbird account as is (POP) and just deal with the side-aggravations separately.

FWIW: I prefer not to use OneDrive, due to the sensitive nature of some attachments, so I guess I cannot rule that out as being part of the problem.

(I use a Win 10 operating system and all upgrades are current, to include the lengthy one from earlier this month.)

Can anyone offer me some suggestions? I'm now a senior citizen and my computer geek days are far in the rear-view mirror.

Thanks in advance!

k

[Acymetric]

I really like the model with the t-tops.

...

OK, sorry. I'm assuming you uninstalled/reinstalled your firewall and anti-virus but left Adobe/Thunderbird alone, the same as they had been before? Have you checked your firewall settings to make sure that port 993 is opened (either open generally or configured to allow connections for Thunderbird)? If you haven't changed anything with your Adobe or Thunderbird settings I don't see why POP vs. IMAP would matter. Assuming you didn't make any changes to Adobe/Thunderbird when you reinstalled your firewall the answer is almost definitely going to be inside the firewall/antivirus settings.

Edit: In fact, the IMAP instructions also indicate that you need to open port 993 so that is where I would start.

[Acymetric]

As for not being able to send from inside of Adobe, is the button disabled, or does it just not doing anything/give an error when you click it?

If you happen to know what version of Adobe, Thunderbird, and Windows (XP, 7, 8, 10) you're running that might also be helpful.

[Kimist]

As for not being able to send from inside of Adobe, is the button disabled, or does it just not doing anything/give an error when you click it?

If you happen to know what version of Adobe, Thunderbird, and Windows (XP, 7, 8, 10) you're running that might also be helpful.

Previously stated, Win 10 system in place to include all current updates.
Thunderbird version 60.6.1 (32-bit)
Adobe Acrobat Reader DC Version 2019.012.20034

The email ("envelope") button IS operative. Generates "How do you want to share your file?" Using "Attach to email" first shows "Your email has been opened in unknown. You can change your email client settings in Preferences." then an error box opens, showing "Server Connection Error. Please verify that Port 993 is available for connection on your machine or contact your administrator."

Main computer settings had/have Thunderbird as default email and Firefox as default browser.

k