diff --git a/Thirdweb/Thirdweb.Extensions/ThirdwebExtensions.cs b/Thirdweb/Thirdweb.Extensions/ThirdwebExtensions.cs
index f87664d..855cdaf 100644
--- a/Thirdweb/Thirdweb.Extensions/ThirdwebExtensions.cs
+++ b/Thirdweb/Thirdweb.Extensions/ThirdwebExtensions.cs
@@ -1905,7 +1905,7 @@ public static async Task<ThirdwebTransactionReceipt> TokenERC20_MintWithSignatur
 
         var payableAmount = isNativeToken ? mintRequest.Quantity * mintRequest.Price : BigInteger.Zero;
 
-        return await ThirdwebContract.Write(wallet, contract, "mintWithSignature", payableAmount, mintRequest, signature);
+        return await ThirdwebContract.Write(wallet, contract, "mintWithSignature", payableAmount, mintRequest, signature.HexToBytes());
     }
 
     /// <summary>
@@ -2105,7 +2105,7 @@ public static async Task<ThirdwebTransactionReceipt> TokenERC721_MintWithSignatu
 
         var payableAmount = isNativeToken ? mintRequest.Price : BigInteger.Zero;
 
-        return await ThirdwebContract.Write(wallet, contract, "mintWithSignature", payableAmount, mintRequest, signature);
+        return await ThirdwebContract.Write(wallet, contract, "mintWithSignature", payableAmount, mintRequest, signature.HexToBytes());
     }
 
     /// <summary>
@@ -2359,7 +2359,7 @@ public static async Task<ThirdwebTransactionReceipt> TokenERC1155_MintWithSignat
 
         var payableAmount = isNativeToken ? mintRequest.Quantity * mintRequest.PricePerToken : BigInteger.Zero;
 
-        return await ThirdwebContract.Write(wallet, contract, "mintWithSignature", payableAmount, mintRequest, signature);
+        return await ThirdwebContract.Write(wallet, contract, "mintWithSignature", payableAmount, mintRequest, signature.HexToBytes());
     }
 
     /// <summary>