LTE attach procedure with no ciphering

I have a case where no ciphering is used in the network as (eea=0), all UEs that set the ESM information flag in the attach request, then the MME send “ESM information request” and it gets the “ESM information response” but after that immediately it send Attach reject with cause “protocol error, unspecified”.

can not using ciphering in the network causes that rejection?