On Modrinth, mods can indicate whether they function client-side, server-side, or both. Dynmap has not marked itself as either client-side or server-side, so some modpack creation tools such as Packwiz are unable to add it to the packs they create, because they don't know whether to include in client or server distributions. Packwiz, for example, fails with this error:
Failed to add project: version doesn't have a side that's supported. Server: unknown Client: unknown
The problem is most clearly illustrated when running a Modrinth API query:
{
"client_side":"unknown",
"server_side":"unknown"
}
I'm happy to create a GitHub issue if that would be more helpful.