Problem scenario
You are using the Coinbase wallet. You try to swap a currency. You click on "Find best price." But you see "You need ETH before you can make a transaction on the Ethereum network."
You do have ETH in your wallet. How do you proceed?
Possible Solution #1
Use the Coinbase Wallet app on a phone instead of the website version. It will provide you with more information on how much ETH you actually need.
Possible Solution #2
Do you have "ETH on Base" or "ETH on Ethereum"? The symbols are as follows:
The top of the above shows ETH on Base. The lower of the above pic shows ETH on the Ethereum network.
If the swap is going to be on the Ethereum network, you need to have ETH on Ethereum -- not Base. Move the ETH to ETH on the Ethereum network.
Possible Solution #3
Add more ETH to your wallet. (Make sure it is on the Ethereum network.)