what are your outgoing mail settings? server (you already stated it perhaps) port and connection security.

Hello! Sorry it took me so long to get back to this, I got caught up in grading... My server is mail.speakeasy.net; my connection security is "none." As I mentioned, part of the problem is that Speakeasy / Megapath (now GTT Communications) is no longer supporting their consumer email functions, so if it's a problem on the outgoing server end (which I suspect it is), then I'm on my own. My main question here is whether there is anything I can do within Thunderbird to make it work again, while we're searching for a comparable server to what Megapath used to be...

Ok, I did not get the port.

So lets try this another way. Please add the troubleshooting information to your post To find the Troubleshooting information:

• Open Help (or click on three-line-icon and select Help)
• Choose Troubleshooting Information
• Use the button Copy to clipboard to select all. Do not check box "Include account names"!
• Paste this in your post.

Okay,,, here's what copied, I hope some of it makes sense to you:

 Application Basics

   Name: Thunderbird
   Version: 52.9.1
   User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:52.0) Gecko/20100101 Thunderbird/52.9.1
   Profile Folder: Show in Finder
   Application Build ID: 20180709124824
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory
   Profiles: about:profiles

 Mail and News Accounts
   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account3:
     INCOMING: account3, , (pop3) mail.speakeasy.net:110, plain, passwordCleartext
     OUTGOING: , mail.speakeasy.net:1025, plain, passwordCleartext, true

   account4:
     INCOMING: account4, , (pop3) mail.speakeasy.net:110, plain, passwordCleartext
     OUTGOING: , mail.speakeasy.net:1025, plain, passwordCleartext, true

 Crash Reports

 Extensions
   ImportExportTools, 3.3.0, true, {3ed8cc52-86fc-4613-9026-c1ef969da4c3}
   Lightning, 5.4.9.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 358400
     browser.cache.disk.filesystem_reported: 1
     browser.cache.disk.smart_size_cached_value: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     extensions.lastAppVersion: 52.9.1
     font.name.monospace.x-western: Arial
     font.name.sans-serif.x-western: Arial
     font.size.variable.x-western: 12
     mail.openMessageBehavior.version: 1
     mail.spotlight.firstRunDone: true
     mailnews.database.global.datastore.id: 050c3131-6857-c546-8c84-a9a9fc287eb
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     media.gmp.storage.version.observed: 1
     network.cookie.cookieBehavior: 3
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1543546213
     places.history.expiration.transient_current_max_pages: 122334
     plugin.importedState: true
     print.macosx.pagesetup-2: PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz4KPCFET0NUWVBFIHBsaXN0IFBVQkxJQyAiLS8vQXBwbGUvL0RURCBQTElTVCAxLjAvL0VO…
     print.print_bgcolor: false
     print.print_bgimages: false
     print.print_command:
     print.print_downloadfonts: true
     print.print_evenpages: true
     print.print_in_color: true
     print.print_margin_bottom: 0.5
     print.print_margin_left: 0.5
     print.print_margin_right: 0.5
     print.print_margin_top: 0.5
     print.print_oddpages: true
     print.print_orientation: 0
     print.print_pagedelay: 500
     print.print_paper_data: 0
     print.print_paper_height: 11.00
     print.print_paper_size: 130744323
     print.print_paper_size_type: 1
     print.print_paper_size_unit: 0
     print.print_paper_width: 8.50
     print.print_printer:
     print.print_reversed: false
     print.print_scaling: 1.00
     print.print_shrink_to_fit: true
     print.print_to_file: false
     print.print_unwriteable_margin_bottom: 56
     print.print_unwriteable_margin_left: 25
     print.print_unwriteable_margin_right: 25
     print.print_unwriteable_margin_top: 25
     security.sandbox.content.tempDirSuffix: {47db345d-c2d5-344d-b763-f10d8490d7b1}

 Graphics

     GPU #1
     Vendor ID: 0x1002
     Device ID: 0x6740

     Features
     WebGL Renderer: ATI Technologies Inc. -- AMD Radeon HD 6770M OpenGL Engine -- 2.1 ATI-1.42.11

     AzureCanvasBackend: skia
     AzureCanvasAccelerated: 0
     AzureFallbackCanvasBackend: none
     AzureContentBackend: skia
     TileHeight: 512
     TileWidth: 512

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 0
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.13.1
     4.13.1

     NSS
     3.28.6
     3.28.6

     NSS Util
     3.28.6
     3.28.6

     NSS SSL
     3.28.6
     3.28.6

     NSS S/MIME
     3.28.6
     3.28.6

go to your account settings. Select the outgoing server (SMTP) and in that pane edit your outgoing server settings.

Try using the settings I got from here https://emailsettings.info/speakeasy-pop-imap-and-smtp-email-settings/

Username: Your email address is your username Server hostname: mail.speakeasy.net Server port: 587 Authentication: Normal Password SSL/TLS: Yes

The existing port of 1025 looks like some sort of proxy port number. Did you have issues at some other time and go looking for ports that worked?

I did a test on the speakeasy servers here https://www.htbridge.com/ssl/graph/IaLaQk0X/1543802423015.html

I see ports 465 on server mail.speakeasy so you could try that as well. That is usually associates with SSL/TLS connection security.

There is also a setting for pop.speakeasy.net on port 587. 587 is a outgoing port. So weird as it might sound. try the pop server as your outgoing server name.

So if the setting I found do not work, you might try some of the more oddball options.

Thanks! Due to lesson planning and all, I probably won't be able to try all this tonight -- but I will get to it this week (with my husband's help, he's the geek in the family) and see if anything works. In case it does, thanks oodles in advance! (and I'll let you know, one way or another...)

Hello again, Well, after digging myself out from under a ton of grading I finally had a chance to try again to solve this thing... I went to edit the server settings and did try to change the server port to 587 (although, oddly enough, after I typed that in it changed itself to 465). I don't know if that actually made any difference, because what solved the problem was changing the authentication from "normal password" to "no authentication." Since no one else uses my home machine, I'm not particularly worried about having no authentication required to send email... And it appears I need to leave it that way, because if I change it back to "normal password" I get the same old problem, no matter what the other settings are.

It is still a mystery why this suddenly came about (I have no idea why Thunderbird suddenly demanded my password in order to send email, and then wouldn't recognize my longtime-and-never-changed password), but at least I can send email again, thank goodness!