DPF message

I have a 2011 GMC 2500 duramax and just had the same thing happen last week. I have a lower limp mode of 55mph in my truck. I'm also on a long road trip with my camper. bottom line I had to stop at a dealer or I would have eventually became disabled. Great system BTW I had to have the DEF tank replaced as it had bad sensors/heating elements. That's the second tank replacement. Last one was about 5 years ago. It's all covered under the extended GMC emissions warranty but that doesnt help when you are on a trip and laid up for 3 days getting it repaired. I was lucky and was still able to keep my reservations but this diesel emissions system with it's countdown to complete disablement is terrible. There has to be a better system. or maybe it's time to go back to gas. They dont have any of this ****.
bottom line you have to go to the dealer. hopefully he can get you in quickly. I wish you luck