Playing on a server I made, both server and client have it, and I set the speeds to max (well, almost max: 3.3999999521443642E38 and 1.79E308), but I'm still getting this error. Are there any mods that conflict with the speed limits? I have Ice and Fire, maybe that's the problem? Not really sure

Ice and Fire takes control of the vehicle speed limit, but you can configure the normal and elytra speed limits in the next release. 😄

Ah ok, I thought that had already been fixed, when looking at the description - but thanks! I'll take a look at Ice and Fire's config to see if I can fix it there

So did I. 😄