Error code P204b reductant pressure.

Has anyone else experienced this error code?
It came on when towing
I cleared the code with my scanner after I had finished towing but has since come back pending and confirmed....
It also errored in the display "AdBlue system fault will not restart in 1000km" but disappeared when I cleared the code.
SQ5 2016
100,000km

Getting the 100k service done on the 8th, searching for information prior to drop off at dealer.
TIA.

Cant help you with much more than to say that error code is related to your Adblue system.

The Adblue systems are notoriously unreliable and tend to have issues not long after warranty expires.