Email with wrong tld hangs three days before Non Delivery Notification

This is normal behavior.  By the standard, servers are supposed to try for four days before giving up.  The design assumption is that servers or network paths may be down.

These days, I think most systems only wait for two days before giving up.

The retry behavior is probably configurable at the shell level.  You will have to ask support to find out how.

Hi and welcome to the UTM Community!

To see the retry configuration in exim.conf

grep -B 1 -A 4 'begin retry' /var/storage/chroot-smtp/etc/exim.conf

The result I got was:

 # --- Retry section ------------------------------------------------------
 begin retry
 
 *         * F,2h,2m; G,16h,1h,1.5; F,3d,6h
 

* = all domains
* = all errors
F,2h,2m = Fixed, retry every 2 minutes for up to 2 hours.
G,16h,1h = Geometrically increasing, retry in 1 hour, 1.5 hours, 2.25 hours, etc. for up to 16 hours.
F,3d,6h = Retry every 6 hours up to 3 days.

After 3 days, the messages are bounced.

To have messages bounced for lawyerbill.com after 16 hours, but to treat all other messages
with the default above, add a line above the default:

lawyerbill.com * F,2h,2m; G,16h,1h,1.5;
*         * F,2h,2m; G,16h,1h,1.5; F,3d,6h

The error "lookup" applies to your incorrect domain name, so you might want to add the following line:

* lookup F,6m,2m
*         * F,2h,2m; G,16h,1h,1.5; F,3d,6h

Let us know what you decide to do and your results.

Cheers - Bob

Great I formation, Bob!   Thank you from all of us.

And Happy Thankksgiving!