What is the exact error message?

The error message is. Sending message failed. Timed out. I am sorry for the time delay I am in Australia.

See if this article helps.

https://support.mozilla.org/en-US/kb/cannot-send-messages

Still checking but I have three other email addresses and they are set up all identical . They are all working fine except this one that wont send

Have not solved the problem. If I deleted the account and installed it again do you think this might work?

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

Since you mentioned you have multiple accounts, please indicate which is the troubled one.

The troubled account is impreza@spin.net.au. I don't no which No. it is but looking at the troubleshooting info it could be No.28. The connection security info is the only difference

 Application Basics

   Name: Thunderbird
   Version: 31.2.0
   User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0
   Profile Folder: Show Folder

             (Local drive)
   Application Build ID: 20141012121702
   Enabled Plugins: about:plugins
   Build Configuration: about:buildconfig
   Memory Use: about:memory

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

   account26:
     INCOMING: account26, , (imap) pop3.spin.net.au:143, plain, passwordCleartext
     OUTGOING: smtp.spin.net.au:25, plain, passwordCleartext, true

   account27:
     INCOMING: account27, , (imap) pop3.spin.net.au:143, plain, passwordCleartext
     OUTGOING: smtp.spin.net.au:25, plain, passwordCleartext, true

   account28:
     INCOMING: account28, , (imap) pop3.spin.net.au:143, plain, passwordCleartext
     OUTGOING: smtp.spin.net.au:25, SSL, passwordCleartext, true

   account29:
     INCOMING: account29, , (imap) pop3.spin.net.au:143, plain, passwordCleartext
     OUTGOING: smtp.spin.net.au:25, plain, passwordCleartext, true

 Crash Reports

 Extensions
   Test Pilot for Thunderbird, 1.3.9, true, tbtestpilot@labs.mozilla.com

 Important Modified Preferences

   Name: Value

     browser.cache.disk.capacity: 358400
     browser.cache.disk.smart_size.first_run: false
     browser.cache.disk.smart_size.use_old_max: false
     browser.cache.disk.smart_size_cached_value: 358400
     extensions.lastAppVersion: 31.2.0
     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
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     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
     mail.openMessageBehavior.version: 1
     mail.winsearch.firstRunDone: true
     mailnews.database.global.datastore.id: 38c81b89-4bcb-493e-b25d-4768d1a5ecb
     mailnews.database.global.indexer.enabled: false
     network.cookie.prefsMigrated: true
     places.database.lastMaintenance: 1416987012
     places.history.expiration.transient_current_max_pages: 50268
     plugin.importedState: true
     security.disable_button.openDeviceManager: false

 Graphics

     Adapter Description: ATI Radeon 2100
     Vendor ID: 0x1002
     Device ID: 0x796e
     Adapter RAM: Unknown
     Adapter Drivers: atiumd64 atiumdag atiumdva atiumd6a atitmm64
     Driver Version: 8.593.100.0
     Driver Date: 5-21-2009
     Direct2D Enabled: Blocked for your graphics driver version. Try updating your graphics driver to version 10.6 or newer.
     DirectWrite Enabled: false (6.2.9200.16571)
     ClearType Parameters: ClearType parameters not found
     WebGL Renderer: Blocked for your graphics driver version. Try updating your graphics driver to version 9.6 or newer.
     GPU Accelerated Windows: 0. Blocked for your graphics driver version. Try updating your graphics driver to version 9.6 or newer.

     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
     4.10.6
     4.10.6

     NSS
     3.16.2.2 Basic ECC
     3.16.2.2 Basic ECC

     NSS Util
     3.16.2.2
     3.16.2.2

     NSS SSL
     3.16.2.2 Basic ECC
     3.16.2.2 Basic ECC

     NSS S/MIME
     3.16.2.2 Basic ECC
     3.16.2.2 Basic ECC

Open the Account Settings and select the troubled account in the left pane. At the bottom of the right screen check which Outgoing Server (SMTP) has been assigned to the account. Once you identified the corresponding server, choose 'Outgoing Server (SMTP) at the bottom of the left pane. Select the server, and verify the 'Connection Security' setting. I'd expect it to be the one set to 'SSL'. Correct that to 'none' or 'plain' like for the other accounts.

Note that with your settings every time you login to your account your password is sent in the clear. Talk to your email provider if they offer a more secure way.

SMTP outgoing server correct. Connection Security set to none. Tested to to send email. Still not working.

Check all your Outgoing Servers, and find the one which is set for 'SSL'. There must be more then one server configured.

All outgoing server setting are set at smtp and security connection set at "none" on all.

 I think I might just delete the problem account and re install.  If that does not work I will delete it altogether.

All outgoing server setting are set at smtp and security connection set at "none" on all.

 I think I might just delete the problem account and re install.  If that does not work I will delete it altogether.

I have deleted the problem email address and re installed it. Did not fix problem.

Will receive mail but won't send.  Checked and rechecked all settings and they are the same as other email accounts which are all working fine.

I must be missing something.

Just to make sure...your original post stated only that replying failed. I take it the problem is a bit broader and all sending on this account fails?

As has been suggested before, account 28 looks odd; it's unusual to use SSL with port 25. SSL would normally use 465. But your ISP or ESP doesn't appear to promote (or support?) SSL or TLS. I think you must change this SMTP setting to "no security" to make it work.

You are looking at SMTP settings, aren't you? It's right down at the end of the list of accounts shown under Account Settings, labelled "Outgoing Server (SMTP)".

When you removed and re-added the offending account, did it not take you through selecting the SMTP server from scratch? There's no reason for Thunderbird to carry on using any previous settings.

Another oddity is that for incoming you're using a server with "pop" in its name yet you connect using IMAP. Chances are the POP and IMAP servers are hosted on the same machine (or machines) and are effectively interchangeable. So whatever it is that uses "pop" in its name is also an IMAP server. But it offends the OCD part of my make-up to see this unnecessary inconsistency. ;-)

I am stumped. This is what I have Outgoing Server is SMTP. Connection security is "None" When I re installed the email account I think some of it might have been automatic. I might do it again and make sure I do it manually. My original post did state it was not replying but it also will not send any emails There is no SSL now all SMTP

Can you post your Troubleshooting Information again?

Christ1.

My problem is one of my email accounts will receive messages but will not send. 

I have three other email accounts. Which have the same settings as the problem account and which receive and send emails without any trouble.

The trouble shooting info for the emails indicates that one account is set up different to the others, but I have checked and rechecked the setting on all accounts and the are identical.

All are set with the outgoing server as SMTP and connection security as "None"

I think that the troubled account's settings are corrupt somehow and won't let the setting be changed.

I have deleted the problem account and manually reinstalled it with the same settings as the other accounts but still have the problem.

What else can I check.

Christ1.

As an experiment I have just changed the Outgoing Server SMTP on the problem account to the name of one of my other accounts that does work.

Now the problem account will receive and send mail with trouble. I might just leave it like that and see what happens.

I'm not sure I can follow what you did.

Now the problem account will receive and send mail with trouble.

Are you saying it is working now or not?

Christ1

This is what I did.

I have three email addresses all have the same settings.

One of these email addresses will not send emails. The other two will send emails.

On the email address that will not send emails I changed the "Outgoing Server (SMTP) to the name of on of the emails that does send emails.

Like this:- Email A,B&C.all with the same settings. Emails A&B will send and receive emails. Email C will only receive emails it will not send emails.

So in the Account Settings section on email C in the section Outgoing Server (SMTP) which was set at C - smtp.spin.net.au I change it to read. A - smpt.spin.net.au.

Email C now sends and receives emails like the others.