that is an error you will get when you have clocked too high or the card has overheated. I have found a lot of 3060’s are very tempermental on overclocking. I would say drop down your memory clock even further to see if you can get a stable clock rate. If you are getting 50 @ 1500 then thats the perfect target, honestly i only had to clock mine that high to get the glitch to work, if you can get it lower then thats better.
Make sure that your PSU is up to the job as well, multi 3060’s take a lot of power, also make sure you are runnning the latest version of t-rex as i found some prior versions were a bit unstable.
Good luck!