Oops, I was wrong to say I can receive mail in the Zoho account. So it is a Zoho problem, both send and receive.

Confirm you have done this: Login to your webmail account via a browser and Enable IMAP Access for your account. I'm assuming you want to connect using IMAP. Usually, you have to select IMAP or POP and then you have to use the server settings for the type you have selected. Confirm what you have selected.

Confirm that your Firewall is not blocking Thunderbird. It should be set to allow or be in a list of allowed apps.

If you needed to enable the imap access and/or set firewall to allow Thunderbird, then retry to GetMessages or Send.

If you still get an error message - what does it say...word for word.

Post the following info: In thunderbird Help > Troubleshooting information click on 'copy test to clipboard' In this forum question, right click in a 'post a Reply' box and select 'paste'. you can remove all info on fonts and printers, but nothing else.

IMAP is enabled in webmail account. Firewall not blocking TB; TB can send/receive in other accounts. Settings confirmed. SMTP is 465 here but I tried 587 also. Error msg: "Sending of the message failed. The message could not be sent using Outgoing server (SMTP) smtp.zoho.com for an unknown reason. Please verify that your Outgoing server (SMTP) settings are correct and try again."

Troubleshooting info:

 Application Basics

   Name: Thunderbird
   Version: 38.2.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20150813074416
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

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

   account6:
     INCOMING: account6, , (imap) imap.gmx.com:993, SSL, passwordCleartext
     OUTGOING: mail.gmx.com:587, SSL, passwordCleartext, true

   account8:
     INCOMING: account8, , (imap) imap.mail.yahoo.com:993, SSL, passwordCleartext
     OUTGOING: smtp.mail.yahoo.com:465, SSL, passwordCleartext, true

   account9:
     INCOMING: account9, , (imap) imap.zoho.com:993, SSL, passwordCleartext
     OUTGOING: smtp.zoho.com:465, SSL, passwordCleartext, true

 Crash Reports

 Extensions
   Filter Button, 1.1.0, true, filter_button@iconparc.de
   Themes Menu, 1.23.1-signed, true, {84625510-7e5d-11e0-a411-0800200c9a66}

 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: 38.2.0
     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: 17
     gfx.direct3d.last_used_feature_level_idx: 0
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 643d7266-062f-4a17-b2e1-845be38ff8e
     network.cookie.prefsMigrated: true
     network.predictor.cleaned-up: true
     places.database.lastMaintenance: 1443371412
     places.history.expiration.transient_current_max_pages: 104858
     plugin.importedState: true
     security.ssl3.ecdhe_ecdsa_rc4_128_sha: false
     security.ssl3.rsa_rc4_128_md5: false
     security.ssl3.rsa_rc4_128_sha: false
     security.tls.version.min: 2

 Graphics

     Adapter Description: Intel(R) HD Graphics 4400
     Vendor ID: 0x8086
     Device ID: 0x041e
     Adapter RAM: Unknown
     Adapter Drivers: igdumdim64 igd10iumd64 igd10iumd64 igdumdim32 igd10iumd32 igd10iumd32
     Driver Version: 10.18.14.4264
     Driver Date: 8-4-2015
     Direct2D Enabled: false
     DirectWrite Enabled: false (6.2.9200.17461)
     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: 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

Tools > Account Settings > Outgoing Server (SMTP) or right click on mail account name in folder pane and select 'Settings' then click on 'Outgoing Server (SMTP).

select the Zoho smtp server to see details. Please confirm the 'User Name' entry has your full zoho email address.

If no, then click on 'Edit' button Remove the current info and make sure the cursor is at the start - so that no blanks get before you type the full email address. click on all OKs

It might be worth editing anyway, just to make sure there are no hidden blank spaces either before or after the email address.

"User name" deleted and re-entered, no spaces. Same result.

I deleted the Zoho account, closed and re-opened TB, and tried to add a new zoho account. As before, TB "Failed to find settings..." even when I entered server settings manually. Disconnecting from internet allows adding the account manually with known good server settings, but as before the account does not send or receive when service is reconnected. The other accounts continue to work normally.

Confirm: you are talking about an email address that is: username at zoho dot com

You do not have a domain, it is just a free zoho email address which you are currently having to access via webmail.

Is the password causing an issue due to specific situation.

Have you enabled a 'Two Factor Authentication' for your zoho account? If yes, then did you create an 'application specific password' to use in Thunderbird?

• https://www.zoho.com/mail/help/adminconsole/two-factor-authentication.html#

Are you what zoho call a 'Federated User' ? Note: If you are a Federated Sign In user, you will not have a 'Zoho' password for your account. Use the Forgot Password link in the login page, to generate Zoho specific password for your account in Zoho. The Federated Login credentials will not work for POP/ IMAP/ Active Sync access. https://www.zoho.com/mail/help/login-to-zoho.html#alink4

general imap info added just in case anyone else wants the info. https://www.zoho.com/mail/help/imap-access.html

Yes, the email address is username at zoho dot com

Not a domain, just a free zoho email address that is accessible via webmail (also accessible via Opera Mail IMAP).

Two-factor authorization is not enabled, and I am not a Federated User.

Thanks for your persistence. Hopefully it rewards us eventually.