A network-cost notice explains what was attempted; it does not prove the wider claim.
Start with public records
Ethereum explains gas as the unit of computational effort required to execute operations. You pay for the work performed even when the transaction ultimately fails.
Source note
On swap interfaces, failures commonly come from quote limits, insufficient native-token balance for network cost, expired deadlines, and unsupported token mechanics.
Source note
The fee model is predictable enough that surprises usually mean the operator skipped a check.
How to use this guide
Compare the source you plan to use against this briefing. Confirm it independently, and stop if the public record does not match the message.
Primary sources