The video portion of a recording may not load when you are trying to play the recording through Windows 7 Media Player with a shared screen, as there are certain limitations with Windows 7 Media Player and higher resolution videos.

How to view recordings with Windows 7 Media Player

Because of limitations with the software and DXVA decoding, Windows Media Player 7 can only support a maximum resolution of 1920 x 1080 pixels. Please refer to Microsoft for more information.

When playing Zoom videos recorded from a shared screen with Windows Media Player, it is not possible to play them if the screen’s resolution exceeds 1920×1080 and the Zoom video was recorded from Zoom.
Windows Media Player may not be able to play the recording if the resolution of the recording is based on the largest screen being shared in the meeting or webinar, so even if the video and screen resolutions were low, the recording may not be able to be played.
Try using another media player such as VLC or Quicktime instead.