"API keys are no longer valid or incorrect" is the most frequent error when you can't connect the exchange account. It's not possible to get the exact reason: exchanges don't tell it to prevent security breaches.
Ensure exchange is available on 3Commas
Similar names often represent different platforms.
Huobi Global and Huobi US, BitMEX and BitMEX, they all are different exchanges.
Check available exchanges.
Disable website translation
It often tries to translate API keys. Even one additional space makes keys invalid.
Don't use IP binding, whitelist, restricted access
When you enable it, you should add all IPs our servers use. Most exchanges don't accept this list as too long. If you can't add every IP, don't use this feature.
Here's the IP list.
Select required permissions
When you create or edit API keys, you can choose what the key allows.
It varies across different exchanges, better to check what permissions to enable on your exchange.
Copy keys fully and without extra characters
If exchange provides a copy button near keys, use it.
Paste keys to a text editor then compare with keys you see on the exchange. If they're different, try to select it more carefully or with a double click.