iTunes Podcast Rejected by Apple
Okay, after a long period of troubleshooting, I determined it was the MP3 file that was having issues. After importing it into GarageBand and exporting it from there, it finally worked! I received the MP3 file from the client. He is a preacher and they recorded it at the church. Then he uploaded it to Google Drive and I downloaded it from there. It sounds like it was not encoded correctly, but I am not an audio expert.