A DNS cache keeps previously obtained name-resolution information for reuse under applicable caching rules. It can reduce repeated lookups, but stored information may briefly differ from a newly changed record elsewhere. Caches can exist at several layers, so restarting one application does not necessarily clear every resolver or device cache involved in reaching a service.
A practical example
After a legitimate server-address change, one device may continue using a cached answer while another obtains a newer one. Comparing the actual hostname resolution and timing is more informative than assuming the two players have different subscription permissions.
A common misunderstanding
Do not repeatedly flush caches to solve an unrelated login or decoding issue. A cache change matters only when stored resolution data is part of the observed failure or planned network update.
Related terms
Further reading
Stable technical definition. Editorial approach