problems with BT broadband and SMTP outgoing mail

I am a newbie to this site and would really appreciate help in dealing with outgoing mail problems I have had for over 3 months:
I have a zoom email account (ie non BT)
BT provide my wireless broadband service at home
I can receive incoming emails, but out going are blocked by the BT gateway - and I get the following message: message undeliverable: 550 relay not permitted

I have the following settings for outgoing mail:
smtp.zoom.co.uk

I understand that BT are restricting use of their gateway for BT email addresses only!
Surely - there must be a workaround? Because otherwise I am forced to abandon my existing email address of 10 years and change it to a BT one??

The zoom technical people suggested I post on this site. BT, when I called about this months ago, said that this is their new policy.

Is there some workaround - because at the moment - I use the internet to reply to messages, and once I have downloaded my messages to outlook, I cannot then respond to them!

Any help most gratefully received.

have you entered your BT info into the My Email requires secure log in for out going mail?????

This restriction is not caused by BT Broadband - Zoom, like most ISPs, will only allow you to connect to their SMTP server when you are on-line with them. BT Broadband will only allow you to send outgoing mail via their servers when you are connected via BT Broadband.

As you are now connecting via BT Broadband, you need to change the SMTP server to mail.btinternet.com and switch on SMTP authentication in your email client, using your BT Internet email address and password.

When I was with BT I used this method to send email with several different (non-BT) email addresses.

This assumes a residential BT Broadband connection - it's different for business users.

Spot on - thanks for this - I had some luck with the BT helpdesk - and the technician - after remotely logging onto my laptop - spend a few minutes shy of an hour doing exactly what you said.
Back in business. Thanks very much!!

No worries - glad it's working OK