Unable to send email from Doro 5516

[Maddy]

I recently got a new Doro 5516 but am unable to send emails from my Plusnet account.  I can receive them with no problems but as soon as I try to send one a message pops up instantly saying 'sending' and then another which says 'failed'.  I have played around with various settings such as port numbers etc:  I contacted Doro and was told to raise the issue with the network provider, however the advisor in the local o2 shop wasn't helpful - in fact he didn't even know how to switch the phone on.  I returned the phone to Mobile Phones Direct who replaced it without any qualms, however, none of the above has resolved the issue.  I notice from the community pages that quite a few people have this problem.

I would be eternally grateful if anyone could tell me what settings I should be using together with any other useful hints.

Many thanks.

[Maddy]

Sorry - still no luck...

[MI5]

@Maddy 

Change relay.plus.net to smtp.plus.net

[Maddy]

Sorry already tried that...

[MI5]

Are you sure username and password is correct @Maddy 

and is your email address a plusnet one?

[Maddy]

The username & password are the same as used to login to my plusnet account and my email address ends .plus.com. I also cannot receive or send using my google account although I have allowed less secure apps used the shortcut link to UnlockCaptcha. I have turned 2-stage security on as well. Any thoughts on this?

[MI5]

I'm reaching the limit of what I can suggest remotely @Maddy 

Is it the same on mobile data and wifi or just one data connection method?

[Maddy]

I think it's time to call it a day. Many thanks for trying.