Something wrong in Express Delivery or in my head?

Hello, my name is Valentine. First of all, i would like to thank the creators of this wonderful site. It's really good that we have so interesting tool to improve our skill of coding Python. Now about my problem. I have spend much time to resolve the task named Express Delivery and when i was at the end of it the testing make really weird thing: at a certain stage of testing, the task stopped and nothing else happened. When canceled, a failure message appeared. The part in which it stops: 3. Weird Test 2/2 checkio (["S ... BB..E"]). In this case, the message shows that my solution "RRRRRRRR" is not suitable. I would like to understand, is it really a failure, or do I need to continue working on this task further? Thank you.