[Ethereum] Fail with error ‘Pancake: TRANSFER_FAILED’

A slippage tolerance option is already added to your code.

In the func

swapExactTokensForETHSupportingFeeOnTransferTokens(amountIn, amountOutMin, path, to, deadline)

amountOutMin is yout slippage tolerance.

When amountOutMin equals 0 it means you will find the best price and execute transaction. If you specify amountOutMin for some number and price will go under your number -> transaction cancels.

Maybe You need to add Heigher Gas

Like :-

sendTransaction.send{
    from: address
    gas: 500000
 }