can't send email Office365 and Mac Mail

[leopardhouse]

My email was moved to Office 365 a while back and my mac mail was all working fine - able to send and recieve emails.  But the last date I have sent an email is 14th January.  For some reason I can no longer send emails although no settings have been changed.  I can still recieve email ok.

For sending email I use smtp.btconnect.com   25.465.587     (no custom port, no SSL, no authentication)

the error I get is The sender address xxxxxxxxxxxxxx@btconnect.com was rejected by the server smtp.btconnect.com.

When I use connection doctor to check my connections it shows all connections as being sucessful.

Please advise how to get around this problem

[Anonymous]

I thought if you were on Office 365 then you should be using a different servers? 

POP setting (incoming)

• Server name: pop.outlook.com
• Port: 995
• Encryption method: SSL

SMTP setting (outgoing)

• Server name: smtp.outlook.com
• Port: 587
• Encryption method: SSL/TLS

Taken form http://btbusiness.custhelp.com/app/answers/detail/a_id/18514/kw/18514 

[leopardhouse · Accepted solution]

Thank you for your reply very much appreciated - I didn't expedt it to work (because I don't use outlook) but I gave it a go and and after messing around for a bit it worked (custom port 587, encryption SSL but still it wouldn't work initially).  When I used authentication password as well it finally worked.