Alt Manager 1.16.5 Forge Altening Crash

[SoapShark]

When i attempt to click on altening on 1.16.5 forge game just crashes. base 1.16.5 works perfectly fine for me. ive tried with and without extra mods, still same crash. error:

The game crashed whilst mouseclicked event handler
Error: java.lang.BootstrapMethodError: java.lang.NoClassDefFoundError: com/thealtening/auth/TheAlteningAuthentication

Exit Code: -1

Crash report: https://paste.ee/p/UGZk7

Latest log: https://paste.ee/p/ftJ5q

(also would like to say that some modules on 1.16.5 forge are abit buggy, such as chest and block esp, they dont point to the right block and instead show up in the distance, but thats not the problem i care about + its prob due to other mods)