Stupid phone & e-mail!!!
I've set my TalkTalk e-mail account up on my HTC Desire HD (on O2) with TalkTalks incoming and outgoing details but when I'm not on my WiFi at home I can receive e-mails but cannot send any as I get a message saying "The account settings are incorrect". I changed the outgoing SMTP server details to O2's (smtp.o2.co.uk) and now when I'm out and about, I can send e-mails fine, but when I'm at home on my wifi, I cannot send any e-mails again as I get the same message! It seems most e-mail accounts with ISP providers only let you send through their SMTP server when you connected to the net over a connection to them. I can't seem to find a way to add multiple outgoing SMTP servers on the phone anywhere! Anyone else have this issue or any ideas to correct it?
The first option that comes to mind to to use a third party SMTP relay. Either that or use an email address which isn't tied to a particular host? You could set your talktalk/02 emails to automatically forward themselves to a gmail or similar address?
I use Windows Live Mail for one key reason - one day I might change ISP and as such I would loose all the emails (besides anything on my PC).
So as said above I'd suggest you look at another email provider and use forwarding rules to get anything new going from your O2 account to this new account - this will scrub out the problem of using your home Wi-Fi as Microsoft/Google/Whoever don't care what connection you are using.
Have you tried setting up your O2 SMTP server with secure authentication (using your O2 username and password)? This is how I have my iPhone set up and that works fine on the O2 mobile signal, or my BT Broadband at home when I'm on wifi.
Might be worth a try?
I actually use my home e-mail client like this because the BT SMTP server is a pain with non-BT/Yahoo e-mail accounts and I use my own domain hosting for e-mail.