Using the latest battletowers-3.4.1-1.17.1.jar, and it is failing to run requiring geckolib3.
But I am using the latest gecko (geckolib-1.17.1-3.0.2).

Any idea where the problem is here?

https://www.curseforge.com/minecraft/mc-mods/geckolib/download/3502631

this version worked for me on 1.17.1 : o