The SiFive forums are for supporting SiFive hardware. They aren’t meant for generic RISC-V questions. RISC-V International has mailing lists where you can ask questions, like sw-dev. See https://riscv.org/technical/technical-forums/ You can also ask questions as issues in the riscv-isa-sim github tree.
Otherwise, I’d ask the usual questions, did you use a linux toolchain, did you static link, did you try enabling spike tracing options to see where it is failing.