Senders state they get "message undeliverable" but I get it???

[TimCA]

People have been telling me that when they send a message to me they get it
kicked back as "undeliverable". BUT it shows up in my in box. How do I fix
this.
Thanks
Tim

 

[Orland, Kathleen]

What is the exact contents of the undeliverable error? It contains error
numbers that are key to solving the problem.

 

[Bill]

What exactly does the bounce message say? Please post the actual message
here. Ask a friend to send you the exact bounce message, or test it yourself
from another email account on a different service, such as a free yahoo
account.

Also, do all senders (to you) get a bounce message, or just people from
certain domains?

You can also try sending that exact bounce message to your IPS provider and
asking them.

Bill