Bosch Front Load Washer Will Not Spin – Error Code E13

My Bosch front loader won't spin, you can hear the motor running. I have checked the coin trap to see if there is any kind of blockage, there is none. I have not pulled off the front bottom cover to see if there is any blockage anywhere else. I keep getting an error code of E13. Initially, I took out all the towels, and ran a small cycle, it drained and spun fine. I put the towels back in and washed. It spun fine after the wash cycle, but then it wouldn't drain or spin on the rinse cycle. I did a reset and am trying it again.