Start with the key source
A Verity Mod API connection failed 401 message is normally later than a loader problem. A loader problem stops Minecraft from starting the right profile, loading Forge or NeoForge, or showing the mod at all. A 401 appears when the Java setup attempts an AI request and the selected provider says the credentials were not accepted. That is why another copy of verity-5.7.3.jar cannot fix the most common 401 cases.
The useful question is not "which mirror has a working Verity Mod download?" The useful question is "which provider did this local setup try to call?" Groq credentials come from Groq Console. OpenRouter credentials come from OpenRouter. A local Ollama route normally needs a running local service and model instead of a cloud API key. If the provider is unknown, return to the current Verity JE instructions or the setup video that matches your installed route before entering any key.