diff --git a/contracts/TokenFactory.sol b/contracts/TokenFactory.sol
index 7be18cc..3dc7d04 100644
--- a/contracts/TokenFactory.sol
+++ b/contracts/TokenFactory.sol
@@ -109,10 +109,12 @@ contract TokenFactory is ProxyFactory, Ownable, ITokenFactory {
         return (_operationalFeeRecipient, _operationalFee);
     }
 
+    // This function should be called with a proper param by a multi-sig `owner`
     function setBaseURI721(string memory uri) external override onlyOwner {
         baseURI721 = uri;
     }
 
+    // This function should be called with a proper param by a multi-sig `owner`
     function setBaseURI1155(string memory uri) external override onlyOwner {
         baseURI1155 = uri;
     }
@@ -242,6 +244,7 @@ contract TokenFactory is ProxyFactory, Ownable, ITokenFactory {
     }
 
     function isNFT721(address query) external view override returns (bool result) {
+        if(query == address(0)) return false;
         for (uint256 i = _targets721.length; i >= 1; i--) {
             if (_isProxy(_targets721[i - 1], query)) {
                 return true;
@@ -275,6 +278,7 @@ contract TokenFactory is ProxyFactory, Ownable, ITokenFactory {
     }
 
     function isNFT1155(address query) external view override returns (bool result) {
+        if(query == address(0)) return false;
         for (uint256 i = _targets1155.length; i >= 1; i--) {
             if (_isProxy(_targets1155[i - 1], query)) {
                 return true;
@@ -309,6 +313,7 @@ contract TokenFactory is ProxyFactory, Ownable, ITokenFactory {
     }
 
     function isSocialToken(address query) external view override returns (bool result) {
+        if(query == address(0)) return false;
         for (uint256 i = _targetsSocialToken.length; i >= 1; i--) {
             if (_isProxy(_targetsSocialToken[i - 1], query)) {
                 return true;