What it means
The node's own estimate of the gas needed came out higher than the cap you allowed, and in most cases that is because the transaction would revert if it actually ran. The estimate blows up because the simulated execution fails.
How to fix it
Do not just raise the gas limit to force it through: a transaction that would revert still reverts, and you pay for it. Find the underlying revert first, commonly a missing token approval, wrong network, or insufficient balance.