I've been trying to have a trust return accepted for almost 2 months with this problem (not giving up yet! :). I tried all of the words in the trust name.   On the THIRD call to the IRS (practitioner hotline), I finally got someone who told me what I have is correct but it's still being rejected.  Client is looking for the EIN letter.  Don't bother calling the help desk or the business lines, they won't tell you anything about the specific return even if you were the prepare for 2020.