What it means
You tried to replace a pending transaction (a speed-up or a cancel reuses its nonce), but the replacement's fee is not enough of an increase. Nodes require roughly a 10% bump or more before they will swap one pending transaction for another.
How to fix it
Raise the fee on the replacement by at least 10% over the original, or simply use the wallet's built-in speed-up or cancel button, which prices the replacement correctly.