diff --git a/src/eco/Relayer.sol b/src/eco/Relayer.sol
index 83391d3..cc0f22e 100644
--- a/src/eco/Relayer.sol
+++ b/src/eco/Relayer.sol
@@ -101,6 +101,7 @@ contract Relayer {
         DstPrice memory p = priceOf[toChainId];
         DstConfig memory c = configOf[toChainId];
 
+        require(c.baseGas != 0; "!baseGas");
         // remoteToken = dstGasPriceInWei * (baseGas + extraGas)
         uint256 remoteToken = p.dstGasPriceInWei * (c.baseGas + extraGas);
         // dstPriceRatio = dstPrice / localPrice * 10^10