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.

I'm so sorry, I don't see where you are referring to... The three line icon seems to be for my google chrome and the "help" tab doesn't include a troubleshooting option.

well perhaps try it in Thunderbird instead of chrome.

Sorry! Here it is:

 Application Basics

   Name: Thunderbird
   Version: 38.5.1
   User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20151228123010
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts
   account1:
     INCOMING: account1, , (imap) imap.gmail.com:993, SSL, OAuth2
     OUTGOING: smtp.gmail.com:465, SSL, OAuth2, true

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

   account3:
     INCOMING: account3, , (imap) imap.mail.me.com:993, SSL, passwordCleartext
     OUTGOING: smtp.mail.me.com:587, alwaysSTARTTLS, passwordCleartext, true

   account4:
     INCOMING: account4, , (imap) imap.secureserver.net:993, SSL, passwordCleartext
     OUTGOING: smtpout.secureserver.net:465, SSL, passwordCleartext, true

 Crash Reports

 Extensions
   Lightning, 4.0.5.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}

 Important Modified Preferences

   Name: Value

     browser.cache.disk.capacity: 358400
     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: 38.5.1
     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
     mail.openMessageBehavior.version: 1
     mail.winsearch.enable: true
     mail.winsearch.firstRunDone: true
     mail.winsearch.global_reindex_time: 1451082575
     mailnews.database.global.datastore.id: 02a3abc2-1723-4248-b3ce-3cefc775fae
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1452466245
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true

 Graphics

     Adapter Description: Intel(R) HD Graphics 5500
     Vendor ID: 0x8086
     Device ID: 0x1616
     Adapter RAM: Unknown
     Adapter Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32
     Driver Version: 20.19.15.4331
     Driver Date: 11-18-2015
     Direct2D Enabled: false
     DirectWrite Enabled: false (10.0.10586.0)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: false
     GPU Accelerated Windows: 0

     AzureCanvasBackend: skia
     AzureSkiaAccelerated: 0
     AzureFallbackCanvasBackend: cairo
     AzureContentBackend: cairo

 JavaScript

 Incremental GC: 1

 Accessibility

   Activated: 1
   Prevent Accessibility: 0

 Library Versions

     Expected minimum version
     Version in use

     NSPR
     4.10.10
     4.10.10

     NSS
     3.19.2.1 Basic ECC
     3.19.2.1 Basic ECC

     NSS Util
     3.19.2.1
     3.19.2.1

     NSS SSL
     3.19.2.1 Basic ECC
     3.19.2.1 Basic ECC

     NSS S/MIME
     3.19.2.1 Basic ECC
     3.19.2.1 Basic ECC

I would have said that account Number three is an account on icloud. (me.com)

Make sure the view menu entry for folders is set to all.

It has no problem with the me.com address, only the icloud.com address, which is different from me.com... I'm not sure what you mean by the menu entry for folders. Where is that? Is it even possible to integrate icloud into thunderbird? Online I'm reading that some people are saying it's not possible.

View menu Select Folders Set the value to ALL folders.

Now I do not use any apple products. That is a personal choice. So I do not have a copy of the UNIX derived operating system or their hardware. I only have access to the web sites.

This one provides the IMAP settings for icloud. they specifically use the me.com imap server. https://support.apple.com/en-au/HT202304 So I see no issue. Just use the settings apple provide. Automatic wizards can only go so far.

I've already tried that. But thanks.

you have already tried what? setting up the correct server settings and it did not work?

Did you have your username set as your email address or the part before the @