A ‘Token Already Exists’ error can occur when an incorrect contract address was added as a custom token.
To find the correct contract address, follow these instructions:
Using Ethplorer.io
Step 1. Enter the name of the token you want to add to your MyEtherWallet interface.
Step 2. Use the contract address (not the creator address) for the custom token field in MEW. Be sure to use the correct decimal count as well.
Using Etherscan.io
Step 1. Enter the name of the token you want to add to your MyEtherWallet interface.
Step 2. Use the contract address for the custom token and be sure to use the correct decimals as well.
Other causes:
This error can also occur if the symbol of your token is the same as a symbol already in our default list. To solve this, try adding the symbol with a ‘2’ after.
Using our above example, instead of ‘SNT’, you would add the token as ‘SNT2’.
This has no actual effect on the token itself but is just a placeholder to make organizing your tokens easier.