i thought i would give this mod a shot if used tick threading before im used to crashes and unstable with this type of work thus i will post the logs in the hope of a fix.

crash-2021-01-16_23.11.14-server.txt
2021-01-16-2.log

MCMT is not 100% compatiple with other mods and cause many issues. I will look at this again when I get to 1.16.4 mod testing.
Also MCMT could have some problems with 1.16.4 on its own as I recently discovert in #43.

this was caused by a players dat file as i found out removing it fixed the issue i can continue testing for you <3 not shure if this mod caused it :(