Fatal error when trying to run Dune utop + argon2

Heya!

I’m getting the following error when running utop

Fatal error: exception Dl.DL_error("/nix/store/9d2vc6l8wjvvwv0sz1lzkf34rabh4yfa-ctypes-foreign-0.21.1/lib/ocaml/5.1.1/site-lib/stublibs/dllctypes_foreign_stubs.so: undefined symbol: argon2_type2string")
Raised at Dl._report_dl_error in file "src/ctypes-foreign/dl.ml.unix", line 44, characters 20-44
Called from Ctypes_foreign_basis.Make.foreign in file "src/ctypes-foreign/ctypes_foreign_basis.ml", line 47, characters 19-47
Re-raised at Ctypes_foreign_basis.Make.foreign in file "src/ctypes-foreign/ctypes_foreign_basis.ml", line 49, characters 50-59
Called from Argon2.Kind.argon2_type2string in file "lib/user/password/argon2/argon2.ml", line 26, characters 4-104

The argon2 file is the exact same file as this one copied over as it is not yet in opam: ocaml-argon2/src/argon2.ml at master · Khady/ocaml-argon2 · GitHub

I am using argon2 together with nix. I am not entirely sure how to debug something like this :face_with_spiral_eyes: