The enclosure in an RSS episode describes the media file a listening app should fetch. Its URL, length and type need to describe the actual delivery file. A working preview inside a private hosting dashboard is not enough to prove that the public enclosure works.
Check the public audio location
Open the enclosure URL through the normal public path. Confirm that it returns the intended audio and does not require your signed-in dashboard session. Check the beginning and ending of the file so a short preview is not mistaken for the full episode.
The enclosure length is the file size in bytes, not the episode duration in seconds. Keep those values in separate notes during a manual check. The media type should match the delivered format rather than an unrelated default copied from another item.
Apple Podcasts lists these enclosure components in its RSS requirements. Use the hosting tool's generated values when available, then verify them after the final audio file is ready.
Recheck after a replacement
If you export a corrected audio file, its size may change even when the spoken content and duration are similar. Confirm that the feed's enclosure information was updated by the publishing workflow.
Avoid changing several episodes at once while diagnosing a single broken media link. Compare one known-good item with the affected item and record the difference.
Keep the approved audio file name, size and publication note together. This gives the next person a clear reference when a listener reports a problem. The goal is agreement between the feed, the file server and the audio you intended to release.