HTTP 504 means a gateway did not receive an upstream response in time. It identifies a timeout in the service path, not necessarily a lack of bandwidth in the home. Determine whether it affects one request or the whole session.
Notice when it occurs
A slow catalogue import and a media stream stopping mid-programme are different operations. Record the stage and elapsed time. If the same operation repeatedly fails after a similar interval, that pattern is useful evidence for the operator.
Avoid oversized repeated imports
Let a supported refresh finish or time out before starting another. Multiple simultaneous imports can make diagnosis harder. If the player offers category selection, use its documented behaviour rather than manually editing unfamiliar server URLs.
Report without guessing the backend
Give support the error, time and affected operation. You do not need to identify the exact upstream server yourself. Keep credentials private and avoid claiming that a router adjustment fixed a timeout unless the result is repeatable.
