My friend and I downloaded the same mod (this one) on the same version of the game (.16 latest) and every time we try to connect we get the error.

Error: "Mods mismatch detected! angelsbioprocessing: Mod contents are different even though versions are the same"

I'm having the same issue with the same error message. I've even transferred the file to my friend to make sure we had the exact file.

Same here it worked fine until a cuple of minutes gao when i changed mod settings. I redownloaded the mod file and reupped it on my server still can't connect with the exact same error message.

Brainfart: I resetted the Mod settings to default now it is working fine again. If i find a minute I'll try and experiment to see which setting had the effect.

It seems to be connected to the alien artifact setting. If it is in default its works fine...if you change it it leads to the mismatch message

the server host has to pass its "mod-settings.dat" settings and replace in C: \ Users \ USER \ AppData \ Roaming \ Factorio \ mods