Slight but persistent delay in sending emails

[Kent Slimm]

My email is now hosted by Microsoft's Office 365 Exchange server. When I tried to configure TB for either Exchange or IMAP, messages would disappear from the server as soon as I moved them from the inbox on one of my devices -- and thus they were unavailable to be read or stored in my other computers. Microsoft was unable to help with this, saying the problem was with TB. I then configured it for POP (and specified in the settings that mail should not be deleted from the server for a week), and things worked fine.

... with one minor annoying exception: Every time I send an email (from a desktop running Windows 8 or from a laptop running Windows 7 -- in both cases using TB), it takes about 15 seconds to finish sending. Most of that time it just hangs, saying "Connected to [name of server]." This does not happen when I send messages from the Exchange web portal, only from my computers using TB. I'm using the SMTP settings I was told to use: port 587 and STARTTLS connection security.

Any idea what's delaying the outgoing mail? I couldn't find any settings on TB or on the Microsoft Exchange dashboard that were relevant.

Thanks!

[DanRaisch]

Sending from Thunderbird through the Microsoft SMTP server is adding a layer of connection that is not present when sending from the web portal. It may very well be that which is causing the delay.

What server name are you using for that SMTP server?

[Kent Slimm]

smtp.office365.com

I had used another email host until recently and there was no such delay. But Microsoft is still insisting this is a Thunderbird issue.

[DanRaisch]

Microsoft will always blame the email client for their own failures. Think about what you just reported here.

I had used another email host until recently and there was no such delay.

If Thunderbird worked with that other host without delays, how would it be a Thunderbird issue when there are delays in sending with Hotmail/Outlook?

[Kent Slimm]

Actually, I don't know if there's a similar delay using a different email client such as Outlook. It's not unreasonable to suspect the problem is with the interaction between this host (Microsoft Exchange) and this client (Thunderbird). But I'm curious whether someone else has experienced a similar delay when using TB with a different host -- or has an idea more generally about speeding up outgoing emails.

[DanRaisch]

I can tell you there is often (but not always) some delay when sending from an Outlook account through Thunderbird. Speeding up sending would, as far as I can tell, have to involved finding a better provider/server.