This issue has been reported by curseforge user gazeluttza in my dms.

Hello,
I'm trying to use shaders/optifine with your mod and I've encountered the below error:

https://pastebin.com/iUv45MhV

OptiFine 1.15.2 is not compatible with forge. This is specified in 1.15.2_HD_U_G1_pre9 changelog.