I just send such a mail using a gmail server. it appears on the gmail site as sent. perhaps you might check the account on gmail and see if the mail is there. Gmail certainly shows is as sent on their web site.

Matt Thanks for the quick reply. Yes it arrived I take it you sent it from Thunderbird, using the gmail as the outgoing server. My next step was to add the servers to Thunderbird to its not a "settings" in Thunderbird. If it works from my Thunderbird, I will mark is as done and assume its just the outlook.com servers.

Thanks very much Matt OK it seems a problem with outlook.com servers or the way they are setup. I am able to send to and from the gmail account.

I notice the port and authentication  settings are different, it maybe the particular account.

Just a follow up for others. My problem originating account is an outlook.com account and this server does not support 0Auth2 authentication. for some reason the address format doesn't work on the "normal" outlook accounts, that use other authentication methods.

Must have tighter or more strict format requirements.

EDIT:

What I said above is not correct 

With Matts help was able to solve the problem. I changed the settings in the smtp server and sent an email and it failed with a timeout (expected) Reset the settings back to what they originally were and was able to send the email, Not sure how or why but it now works, it sent to normal addressees before, now it sends to all

Ok I just sent another mail, this time from a hotmail account (outlook.com)

On logging into the web site the outlook.com site shows the mail as sent. Did it arrive?