Frequently Asked Questions.
Every block explorer built by Etherscan ( eg. BscScan, PolygonScan, HecoInfo ) requires a different account to be created and hence a different set of API keys
The additional endpoints available under any API PRO subscription
are only available to the Polygon POS Chain mainnet, and not supported on testnets such as the Mumbai testnet.
A technical glitch may have occurred in the key creation process. In this case, try deleting the key and generating a new one