[Ethereum] Out of gas error for a view function

having a problem with calling a method of my deployed contract in the main Ethereum network.

I have a 'view' function which returns user's refund balance, everything worked fine in my local blockchain (Ganache), but doesn't work in the main network 🙁

So here I call that method from web3:

this.myContract.methods.checkFunds().call().then((refunds) => {
      return refunds;
});

this is my contract function and here I call another contract function:

mapping(address => uint256) private funds;

function checkFunds() external view returns(uint256) {
    return contract2.checkFunds(msg.sender);
}

here is that contract2:

function checkFunds(address _owner) public view returns(uint256) {
    return funds[_owner];
}

if user doesn't have funds then it should return 0 and it's uint256, then it should be ok, but I get such an error:

Uncaught (in promise) Error: Returned values aren't valid, did it run Out of Gas?
at ABICoder.decodeParameters (app.js:37038)
at Contract._decodeMethodReturn (app.js:36366)
at Method.outputFormatter (app.js:36719)
at Method.formatOutput (app.js:9201)
at sendTxCallback (app.js:9511)
at app.js:96628
at inpage.js:1
at inpage.js:1
at o (inpage.js:1)
at inpage.js:1

and I have the latest version of web3 btw:"react-web3": "1.2.0",

Do view functions cost gas ? That's strange, because I call another method of that contract to read items and it doesn't cost anything.

thank you!