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Application Basics

   Name: Thunderbird
   Version: 38.3.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150928051427
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

 Mail and News Accounts

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

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

   account4:
     INCOMING: account4, , (imap) imap.gmail.com:993, SSL, OAuth2
     OUTGOING: smtp.googlemail.com:587, alwaysSTARTTLS, passwordCleartext, true

 Crash Reports

 Extensions
   Display Quota, 0.3.7, true, {c1ac4523-76c2-9995-adbd-d93bf5141bea}
   GlodaQuilla, 0.3.3, true, glodaquilla@mesquilla.com
   Lightning, 4.0.3.1, true, {e2fda1a4-762b-4020-b5ad-a41df1933103}
   Remove Duplicate Messages, 0.1.14, true, {12345678-1234-1234-1234-123456789abc}
   Remove Duplicate Messages (Alternate), 0.3.12, true, {a300a000-5e21-4ee0-a115-9ec8f4eaa92b}
   Spanish (Venezuela) spell check dictionary, 1.1.18, true, es-ve@dictionaries.addons.mozilla.org
   Test Pilot for Thunderbird, 1.3.10, false, tbtestpilot@labs.mozilla.com

 Important Modified Preferences

   Name: Value

     accessibility.typeaheadfind.flashBar: 0
     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: 38.3.0
     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: 18
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: dc4a9cbc-2fac-47b3-919e-5772edd109c
     mailnews.database.global.views.conversation.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: 1365178369
     places.history.expiration.transient_current_max_pages: 104858
     plugin.disable_full_page_plugin_for_types: application/pdf
     plugin.importedState: true
     plugins.update.notifyUser: true

 Graphics

     Adapter Description: Intel(R) HD Graphics Family
     Vendor ID: 0x8086
     Device ID: 0x0102
     Adapter RAM: Unknown
     Adapter Drivers: igdumd64 igd10umd64 igd10umd64 igdumdx32 igd10umd32 igd10umd32
     Driver Version: 8.15.10.2509
     Driver Date: 8-31-2011
     Direct2D Enabled: false
     DirectWrite Enabled: false (6.2.9200.17461)
     ClearType Parameters: Gamma: 2200 Pixel Structure: R
     WebGL Renderer: false
     GPU Accelerated Windows: 0

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

 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
     3.19.2 Basic ECC
     3.19.2 Basic ECC

     NSS Util
     3.19.2
     3.19.2

     NSS SSL
     3.19.2 Basic ECC
     3.19.2 Basic ECC

     NSS S/MIME
     3.19.2 Basic ECC
     3.19.2 Basic ECC

There are two Gmail accounts (account3 and account4). Which is the one with the problem?

Account 3

Underneath Account Settings, try to change the 'Authentication type' to 'OAuth2' for both, incoming and outgoing server.