Koin’s current plugin was built for Ktor 2.x, but you’re using Ktor 3.x. In Ktor 3 the ApplicationEnvironment.getMonitor() method was removed, so Koin crashes.

• Either downgrade to Ktor 2.3.x and keep using Koin 3.x,

• Or upgrade to Koin 4.1+ (with the new koin-ktor3 module) to work with Ktor 3.