Please post your Troubleshooting Information. At the top right of the Thunderbird window, click the menu button , then select Help > Troubleshooting Information. Press the "Copy text to clipboard button" and paste the information into your reply.

For IMAP, use the correct Yahoo servers and change the authentication to OAuth2:

https://support.mozilla.org/en-US/questions/1278588

Support for OAuth with Yahoo POP accounts is available with the latest TB beta, and is expected in an upcoming release version.

Application Basics

   Name: Thunderbird
   Version: 52.5.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0
   Profile Folder: Open Folder

             (Local drive)
   Application Build ID: 20171121193617
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory
   Profiles: about:profiles

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3) pop.mail.yahoo.com:995, SSL, passwordCleartext
     OUTGOING: , smtp.mail.yahoo.com:465, SSL, passwordCleartext, true

   account2:
     INCOMING: account2, , (none) Local Folders, plain, passwordCleartext

   account3:
     INCOMING: account3, , (imap) imap.mail.yahoo.com:993, SSL, passwordCleartext
     OUTGOING: , smtp.mail.yahoo.com:465, SSL, passwordCleartext, true

   account4:
     INCOMING: account4, , (pop3) mail.comcast.net:995, SSL, passwordCleartext
     OUTGOING: , smtp.comcast.net:465, SSL, passwordCleartext, true

   account5:
     INCOMING: account5, , (pop3) pop.mail.yahoo.com:995, SSL, passwordCleartext
     OUTGOING: , smtp.mail.yahoo.com:465, SSL, passwordCleartext, true

 Crash Reports

 Extensions
   ImportExportTools, 3.3.2, true, {3ed8cc52-86fc-4613-9026-c1ef969da4c3}
   Lightning, 5.4.5, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}
   Manually sort folders, 1.1.1, true, tbsortfolders@xulforum.org
   Remove Duplicate Messages (Alternate), 0.4.1, true, {a300a000-5e21-4ee0-a115-9ec8f4eaa92b}

 Important Modified Preferences

   Name: Value

     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
     dom.apps.reset-permissions: true
     extensions.lastAppVersion: 52.5.0
     font.internaluseonly.changed: false
     font.name.monospace.el: Consolas
     font.name.monospace.x-cyrillic: Consolas
     font.name.monospace.x-unicode: Consolas
     font.name.monospace.x-western: Consolas
     font.name.sans-serif.el: Calibri
     font.name.sans-serif.x-cyrillic: Calibri
     font.name.sans-serif.x-unicode: Calibri
     font.name.sans-serif.x-western: Calibri
     font.name.serif.el: Cambria
     font.name.serif.x-cyrillic: Cambria
     font.name.serif.x-unicode: Cambria
     font.name.serif.x-western: Cambria
     font.size.fixed.el: 14
     font.size.fixed.x-cyrillic: 14
     font.size.fixed.x-unicode: 14
     font.size.fixed.x-western: 14
     font.size.variable.el: 17
     font.size.variable.x-cyrillic: 17
     font.size.variable.x-unicode: 17
     font.size.variable.x-western: 17
     general.autoScroll: false
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 77e089b6-f8fa-4689-bc02-9d72c585882
     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: 2
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1580329982
     places.history.expiration.transient_current_max_pages: 122334
     plugin.importedState: true
     security.sandbox.content.tempDirSuffix: {b27df355-114e-4edf-be13-e4eae30f83aa}

 Graphics

     GPU #1
     Description: NVIDIA NVS 5200M
     Vendor ID: 0x10de
     Device ID: 0x0dfc
     RAM: 1024
     Drivers: nvd3dumx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um
     Driver Version: 9.18.13.2762
     Driver Date: 10-28-2013

     Features
     Direct2D: false
     DirectWrite: true (6.2.9200.22852)
     WebGL Renderer: Google Inc. -- ANGLE (NVIDIA NVS 5200M  Direct3D9Ex vs_3_0 ps_3_0) -- OpenGL ES 2.0 (ANGLE 2.1.0.2a250c8a0e15)

     AzureCanvasBackend: skia
     AzureCanvasAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: skia

 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

christ1 said

Please post your Troubleshooting Information. At the top right of the Thunderbird window, click the menu button , then select Help > Troubleshooting Information. Press the "Copy text to clipboard button" and paste the information into your reply.

I am now having a seperate problem. Not when I go to add the account, it says 'incoming server account already exists', yet nothing shows up in the 'acccount' page. I have tried updating to a newer version of Thunderbird, but that didn't help.

davidhainlin said

I am having 2 problems. In trying to add a yahoo POP account, I kept getting the error message "username or password are incorrect". This is false. I then tried IMAP, and got the same message. I have double checked all my information, and it is all correct. Any ideas?

Name: Thunderbird Version: 52.5.0

First of all create a full backup of your Thunderbird profile. https://support.mozilla.org/kb/profiles-where-thunderbird-stores-user-data#w_backing-up-a-profile

Then upgrade to the latest Thunderbird release version (currently 68.4.2). Download the installer from https://www.thunderbird.net/ and run it.

As per your Troubleshooting Information there are two Yahoo POP accounts (account1, and account5).

Are these different accounts, or is the second essentially the same as the first one?

Wrt the the Yahoo IMAP account (account3) change the Authentication type to OAuth2 for both, incoming server (IMAP), and outgoing server (SMTP) once you're running the latest version.