No audio or video on a 20 minute recording saved but

[NWhysel-CUNY]

I recorded several sessions from a conference to the cloud. On some, the audio and video worked but others I have 20 minutes of just my zoom name with no audio or video. I am sure we shared screen and audio, because it sent the presentations to the projector and we were doing that via zoom share. Is there any other reason it may not have recorded at least video when I recorded to cloud?

[NWhysel-CUNY]

Each recording had at least 20 minutes of just my zoom name, no audio/video and saved to the cloud as a 25Mb+ file.