SCEP-server do not works on 38.1 tile

Hello. I`m using scep-servers on my Mikrotik CCR1109-8G-1S and CCR1009-8G-1S-1S+. After upgrade to version 6.38 clients cant renew their certificates with an error message “scep client failure: requesting-certificate-failed”. When I tried to open scep URL in browser there are message “Error 501: Not Implemented”. 6.38.1 has the same error. I tried set up scep-server on RB951G - it works fine on 6.38.

Because of it I have to downgrade CCRs to 6.37.3. Please help