Example:
https://polygonscan.com/tx/0xf3a7a37d7a12950e29d477349562bc2ab09e3cac140c1567f39ae1e3614fe01e
The error here is a slippage error. Due to high slippage on the exchange rate, the returned amount would be lower than the defined slippage. For that reason, the tx was rejected by the DEX.