Aikars flag doesn't work

Hi so I just bought new server for minecraft I’ve installed Pterodactyl panel and I’ve also tried to use aikars flag.
Server is 1.16.4 paper #416 build.
Short while after I start the server it’s crashing with “exit code 1”.
I did same thing on my pc and console output is “Could not find or load main class”

You most likely copied the flags wrong then. How are you starting your server? Please paste the command

java -Xms4G -Xmx4G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -Dusing.aikars.flags= -jar paper.jar nogui

Read the section right below the flags for Pterodactyl users

I’ve deleted those flags “-Dusing.aikars.flags=” and server is running properly. What are thoes flags? Is it important?