I have several of the TMQAM modulators running 64 QAM and recently I added a TMQAM/asi modulator, which I want to operate at 256 QAM, but I can’t get it to function

When running 256 QAM, it is necessary to change the BD RATE to 5.3606 instead of the 5.057 baud rate or symbol rate used for 64 QAM.