550 Relay not permitted

[#1]

Hi
Anyone else getting this
Often when I email someone , it bounces and comes back with 550 relay not permitted
Is this to do with plus net?
This is my normal plusnet email address and I am using Outlook
Bob

[#2]

If you are trying to use PN's outgoing server from another network (eg are you are using a laptop away from home) then you will get this error with the standard setup.
What servers do you have set up on Outlook for you email account?
What network connection are you using?
If you are using WiFi at home are you sure you are connected via PN and not your neighbours open WiFi? !!

[#3]

Can you post sanitised headers from the bounced email? replace any email addresses with xxxx@xxxx.com or similar.