Sorry for this issue. This warning surfaces due to an error (revert) being returned on an eth_estimateGas call from the JSON RPC Provider configured in your browser-based wallet. Sometimes errors like this can be caused by a flaky provider. If there is a different provider you can configure in your Metamask or similar, that could resolve it. Some networks are less reliable than others for returning sound data from eth_estimateGas unfortunately so in some cases users will need to bypass this warning but our logic is to surface it any time that JSON RPC call indicates the transaction would revert.
Hope that is helpful. Please let me know if you have any further issues.