Can you post your Troubleshooting Information? Help (Alt-H) - Troubleshooting Information

Application Basics

   Name: Thunderbird
   Version: 38.0.1
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150608103712
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (pop3) pop.123-reg.co.uk:110, plain, passwordCleartext
     OUTGOING: smtp.123-reg.co.uk:587, plain, passwordCleartext, true

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

 Crash Reports

 Extensions
   Lightning, 4.0.0.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     browser.cache.disk.capacity: 358400
     browser.cache.disk.smart_size_cached_value: 266240
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     extensions.lastAppVersion: 38.0.1
     font.internaluseonly.changed: true
     font.name.monospace.el: Consolas
     font.name.monospace.tr: Consolas
     font.name.monospace.x-baltic: Consolas
     font.name.monospace.x-central-euro: 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.tr: Calibri
     font.name.sans-serif.x-baltic: Calibri
     font.name.sans-serif.x-central-euro: 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.tr: Cambria
     font.name.serif.x-baltic: Cambria
     font.name.serif.x-central-euro: 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.tr: 14
     font.size.fixed.x-baltic: 14
     font.size.fixed.x-central-euro: 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.tr: 17
     font.size.variable.x-baltic: 17
     font.size.variable.x-central-euro: 17
     font.size.variable.x-cyrillic: 17
     font.size.variable.x-unicode: 17
     font.size.variable.x-western: 17
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: c9549175-77fd-4f62-ada8-f5dfe34cd14
     mailnews.database.global.views.conversation.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     mailnews.database.global.views.global.columns: {"threadCol":{"visible":true,"ordinal":"1"},"flaggedCol":{"visible":true,"ordinal":"3"},"attachmentCol":{"visible":false…
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1434026996
     places.history.expiration.transient_current_max_pages: 34991
     plugin.importedState: true

 Graphics

     Adapter Description: Intel(R) HD Graphics 3000
     Vendor ID: 0x8086
     Device ID: 0x0116
     Adapter RAM: Unknown
     Adapter Drivers: igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32
     Driver Version: 9.17.10.2932
     Driver Date: 12-12-2012
     Direct2D Enabled: true
     DirectWrite Enabled: true (6.2.9200.17292)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: false
     GPU Accelerated Windows: 1/1 Direct3D 11

     AzureCanvasBackend: direct2d 1.1
     AzureSkiaAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: direct2d 1.1

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 0
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.10.8
     4.10.8

     NSS
     3.18.1 Basic ECC
     3.18.1 Basic ECC

     NSS Util
     3.18.1
     3.18.1

     NSS SSL
     3.18.1 Basic ECC
     3.18.1 Basic ECC

     NSS S/MIME
     3.18.1 Basic ECC
     3.18.1 Basic ECC

I will guess as 123 really do not explain their setting in any way.

I sat through their tutorial video and in that leaved that they use SSL for their IMAP account. T^hey do not mention that in their general settings and they appear to have skipped over POP entirely.

So here is a guess.

Tools menu (alt+T) > account settings > server settings and change the connection security to SSL/TLS (that is what they use for IMAP. and port 993 as that is the SSL port for Secure (SSL) connection. See if that works at all. It might not as I am guess.

Another guess is disable any password aching software you might have like Nortons Vault and disable email scanning in your anti virus.

Thanks but that didn't work. Sorry you had to sit through that video. I'm thinking, would it work if I just uninstalled TB and then reinstalled it? If that's the case, I need to know how to export all of my emails so I have them somewhere. I don't know if I need to put this as a new question or not.

No point uninstalling as your mail and settings are not touched by the process.

More useful might be to try the following:

• Restart Thunderbird with add-ons disabled (Thunderbird Safe Mode). On the Help menu, click on "Restart with Add-ons Disabled". If Thunderbird works like normal, there is an Add-on or Theme interfering with normal operations. You will need to re-enable add-ons one at a time until you locate the offender.
• Restart the operating system in safe mode with Networking. This loads only the very basics needed to start your computer while enabling an Internet connection. Click on your operating system for instructions on how to start in safe mode: Windows 8, Windows 7, Windows Vista, Windows XP, OSX

If safe mode for the operating system fixes the issue, there's other software in your computer that's causing problems. Possibilities include but not limited to: AV scanning, virus/malware, background downloads such as program updates.