Problems with yield farm fork

Hello! Sorry for my bad English

After some weeks of working I managed to create my own yield farm on Polygon by forking pancakeswap and adding some extra features. I created a pair on quickswap with 1 usdc and 1000 of my tokens (just for testing the farms), and added liquidity (1usdc + 1000mytokens) to receive the LP token. Then I managed to stake the new MYTOKEN-USDC LP Token in a custom farm that make me earn MYTOKENs. The problem is that after i stake for the first time any quantity of MYTOKEN-USDC LP in the farm, then I can't do nothing else. I see MYTOKEN raising but I can't harvest, nor I can't add more liquidity or withdraw the added liquidity. I keep getting the error in Metamask "ALERT: Transaction Error. Exception thrown in contract code.". Then the only thing I can do is emergencyWithdraw from MasterChef, then it allows me to stake the LP once again (but just one time, as said before :( ). Anyone knows what could it depends on? Thanks a lot!