Running tModLoader on a cracked copy often presents specific hurdles: Steam API Detection

– Using tModLoader with a pirated copy will cause constant issues: mismatched versioning, missing Steam/GOG API hooks, inability to download mods from the official Mod Browser, and crashes. The tModLoader developers do not provide support for cracks.

Unless the person you are playing with has the exact same crack, the exact same mod list, and has disabled Steam authentication in the serverconfig.txt , you will not connect. Even then, desyncs happen every 5 minutes.

If you genuinely love Terraria and want to experience the incredible creativity of its modding community (Calamity alone offers 40+ hours of new content), do the right thing:

Installing tModLoader (TML) for a non-Steam (cracked) version of Terraria 1.4.4.9