diff --git a/crates/erc20_payment_lib/src/eth.rs b/crates/erc20_payment_lib/src/eth.rs
index a227215a..2803e71d 100644
--- a/crates/erc20_payment_lib/src/eth.rs
+++ b/crates/erc20_payment_lib/src/eth.rs
@@ -26,9 +26,8 @@ pub async fn get_balance(
         "Checking balance for address {:#x}, token address: {:#x}, check_gas {}",
         address,
         token_address.unwrap_or_default(),
-        check_gas
+        check_gas,
     );
-
     let gas_balance = if check_gas {
         Some(
             web3.eth()
@@ -63,8 +62,8 @@ pub async fn get_balance(
             .map_err(err_from!())?;
         if res.0.len() != 32 {
             return Err(err_create!(TransactionFailedError::new(&format!(
-                "Invalid balance response: {:?}",
-                res.0
+                "Invalid balance response: {:?}. Probably not a valid ERC20 contract {:#x}",
+                res.0, token_address
             ))));
         };
         Some(U256::from_big_endian(&res.0))
diff --git a/yatestnet/contracts/hardhat.config.js b/yatestnet/contracts/hardhat.config.js
index 3e9fb41e..77a68932 100644
--- a/yatestnet/contracts/hardhat.config.js
+++ b/yatestnet/contracts/hardhat.config.js
@@ -1,4 +1,4 @@
-require('dotenv').config({path:'.env'})
+require('dotenv').config({path: '.env'})
 
 require("@nomicfoundation/hardhat-toolbox");
 
@@ -12,6 +12,11 @@ module.exports = {
             url: process.env.YATESTNET_RPC || "http://127.0.0.1:8545",
             accounts: [private_key],
             chainId: 987789
+        },
+        mumbai: {
+            url: process.env.MUMBAI_RPC || "http://127.0.0.1:8545",
+            accounts: [private_key],
+            chainId: 80001
         }
     },
     solidity: {