ChatGPT, Claude, and Gemini API Key Errors and Access Restriction Troubleshooting Checklist

Have you ever had that crash moment too: the code was running fine, then suddenly you get “API key invalid,” “401,” “403,” “rate limit.” After a round of checks, you realize it feels like you’re talking to thin air. I’ve broken down the common pitfalls by product—go through this checklist once and you can usually bring it back.

How to Focus on the Key Points of Common ChatGPT API Errors

On OpenAI’s side, the three most common ways things go wrong are: using the wrong key, incorrect project permissions, and the network being blocked.

• Confirm whether the key was copied with missing characters, or you’re using an “old key” as if it were a “new key”
• Be clear about which endpoint you’re calling—if your model permissions aren’t sufficient, you’ll get 401/404 directly
• If a company network/proxy blocks the request, it may show up as 403 or timeouts—switch networks and you’ll know immediately

Claude Call Failures Are Usually Not Because You Wrote the Code Wrong

Claude is more like a building with “strict access control”: region, organization permissions, or nonstandard headers can all stop you. If you hit a 403, don’t rush to doubt your life choices.

• Check that you’re using the officially required headers and version field
• It’s very common for the same key to be overwritten in different environment variables, especially in multi-project/multi-session development
• If you’re integrating inside a bot framework (such as some plugin ecosystems), it’s often a “fake error” caused by “the key not being read”

For Gemini Errors, Just Look at Two Things

With Gemini, the most common issues are quota and project binding.

• In the console, confirm the API is enabled and that billing/project selection isn’t wrong
• If 429 shows up frequently, don’t brute-force it—implement retry with backoff or reduce concurrency, otherwise you’ll just keep hitting a wall

If Midjourney Generation Fails, Don’t Just Keep Retrying

Midjourney isn’t a traditional API, but “service unavailable/can’t generate images” is mostly related to account permissions, Discord status, and command format.

• Confirm your subscription is valid and that you’re using commands in the correct channel
• When Discord is acting up, switching regions/networks is often more useful than疯狂 resending

My Own Lazy Troubleshooting Order

When I see an error, I troubleshoot in this order: “whether the key is being read → whether permissions/project match → whether the network/region is restricted → quota and request rate,” so I don’t spin in logs.

If you’re stuck on issues like subscriptions, regional restrictions, or account activation—problems where you get blocked before you even start—go take a look at Titikey. A lot of people save a ton of time at that step.