How to use samply in offline mode?

I'm (have to) profiling on an offline machine using samply 0.13.1. The samply binary and Windows Performance Toolkit is directly copied and installed on the target machine. To use the firefox profiler ui not from https://profiler.firefox.com, I serve its static files myself. However, if I load the profile.json into the locally served profiler UI, I can't get the correct function name. I can see the warnings in profiler UI's web console says: SymbolsNotFoundError: Could not obtain symbols for xxx.pdf/XXXXXXXX. I assume it somehow still depends on samply's local service in 127.0.0.1:3000? Is it possible to use samply in offline mode in my case? Samply is a great profiler; I wish it could work in totally offline mode.