If you encounter the “Invalid Method Parameter(s)” or “JSON-RPC error” error when trading on the Polygon Network, Please change the RPC URL that might help out:
Open Metamask, and Click avatar icon on top right;
Click the “Settings → Networks → Polygon Network”;
Find the “New RPC URL”, and change to others. You can choose one of the following:
Please note that both error messages indicate the Polygon network issue that is not related to SynFutures Dapp. If error persists after trying both methods, please contact SynFutures team via our community (🤖: http://discord.gg/uu5ZNaTZE3).