@Paul_Guilfoyle THANK YOU for the detailed post above!!
I purchased two Eufy 11 Robovacs and I LOVE them. However one vac I bought as reconditioned, thus less expensive and it only had a 90 day warranty. After about one year of use with that vac, I was having the same stuck roller brush fault after about one minute of operation. I cleaned all the recommended things and still the error code. Then found a you tube video that showed how to clean bearing shaft inside the end of the roller brush. Did that too. Still got the code.
Finally got on this site, queried my problem and got to this forum. I read through your post several times, then put on my big girl pants and dove into the project. I was surprised how much hair and dust bunny material was inside of the vac. I was a bit dismayed at how little hair/fiber material was in the actual motor & shaft. Figured that was no way the problem since there was not much there. I vacuumed out everything, very carefully removed all hairs and fibers from shaft, gears, etc. and re-assembled everything. Crossed my fingers, held my breath and turned “Lucy 2” (mine are named LOL!) on. It seems to be working again. Ran through a whole cleaning cycle and returned to base with no error code. I am cautiously optimistic 
**NOTE - If my vac was still under warranty I would have contacted Anker support/service, but since that was not an option decided to try this fix, because as I said above I LOVE my Eufy 11’s and really wanted to keep it.
Just wanted to say thank you for your post, you may have saved me a lot of sadness and money to boot!