Unable to SEND emails since switch to EE

[#1]

I think I'm going to have to move my aunt's mailbox. At least she's been using a domain name email address all the time which was forwarding to her Plusnet/Greenby email address so she won't have to give everyone a new email address.

Incidentally, although my aunt is now with EE, I still have Plusnet Broadband and her email address won't even work when I test it from my end connected to a Plusnet connection.

[#2]

I've had difficulties sending mail today -- and I'm still with Plusnet broadband -- at first using a client (Apple Mail) and later using Greenby's Roundcube webmail.

Apple Mail initially returned the message that it was having difficulty contacting the SMTP server. On further investigation it was telling me that the SMTP server's certificate could not be trusted. I overrode this and the mail was sent.

When I tried sending via Greenby's webmail it did throw up several "server error" messages, but eventually sent my test email.

Tried this on two computers -- same difficulties, same results!

[#3]

Following the transfer to EE I also found I was unable to send emails from my Plusnet account.  Attempts produced message: 

" Server error: '550 <email address> recipient rejected - relay denied'.

Having unsuccessfully tried many of the combinations detailed in this blog I finally resorted to the Greenby chatbot and was agreeably surprised to find that after a few prods it came up with a solution that worked for me which I paraphrase below:

" The correct outgoing (SMTP) server for your Plusnet email account is:

* Outgoing Mail Server: mail.plusnet.enmail.co

* Port: 25

* SSL/TLS / Secure Connections: Disabled

* SPA (Secure Password Authentication): Disabled

* My outgoing server (SMTP) requires authentication:  Enabled.

* Select the option to "Use same settings as my incoming mail server" (or re-enter your full email address and password specifically for the outgoing server)."

I hope this may be useful to some users.  It would have been useful if Plusnet /Greenby could have published this information before the changeover, rather than leaving many of us floundering afterwards.  Shocking customer service!

[#4]

That is one option I have not tried, nor will I. 😐

It has been commented on here that disabling security may work but it is not exactly... secure.  or recommended!

I managed to send some emails to my own gmail address from webmail but one I sent to someone else has bounced back: with this message:

This is the mail system at host gateway1.enmail.co.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below...]
To protect our users from spam... mail sent from your domain has been temporarily rate limited.