Globalnet email

[#1]

Hi all.

Today my forced move to BT happened, even though I was quite happy with Globalnet/plusnet.  Thankfully, I’m still receiving email on my Globalnet email address through webmail and outlook.  However, I’m unable to send or reply to any.  It says to all email addresses that it’s not a valid email address and rejected by the server.  

Do I need different settings? Please advise.  I’m not techy so please keep it simple!  Thanks.  

[#2]

Typically the answer would have been use a Greenby SMTP server like mail.enmail.co ( for send / reply ) 
or try via Greenby webmail : https://webmail.greenby.com/

But here I don't know if this applies given the Globalnet email server : mail.globalnet.co.uk
is hosted by Plusnet, suggesting Globalnet emails are not migrated to Greenby.

It might be worth archiving or printing important emails now whilst you can see them.

[#3]

Greenby hasn't moved yet, so all will continue as normal except for sending (see the previous reply).

[#4]

But I still can’t send any mail so it’s not the same.  

[#5]

If you can collect email via : mail.globalnet.co.uk

Is it possible to send emails via : mail.globalnet.co.uk   Port 587 with Encryption NONE aka SSL OFF ?

[#6]

I’m trying these settings….

Incoming Server (POP3) Port 110	Incoming Server (IMAP) Port 143	Outgoing Server (SMTP) Port 25 or 587	Username Format	Secondary Format	Email Address Format	Mail Capacity
Globalnet	mail.globalnet.co.uk		smtpmail. globalnet.co.uk	[full email address]		[username]@ globalnet.co.uk	250MB

[#7]

Still says cannot send mail …..@Globalnet is not a valid email address and has been rejected by the server.

Incoming mail seems to have stopped as of this morning too.  
 Tearing my hair out now.  Who can I talk this through with?