Indoor Camera - No recordings in last 30 days

Quite frequently when I try to view previous recordings from indoor cameras, there is a message that says the camera does not have any recordings in the last 30 days, though I know there have been several.  On occasion, I'll be able to access those recordings without any problem.   I have 3 indoor cameras that do this and have been trying to remember to share the videos every time I get a notification, just so that I can access them reliably when needed.  Is this something that there is a known cause for?