Yes, its set for 00:00:00 to 23:59:59... different day different time for different duration, its loosing signal. so i think, it couldn't be schedule issue.
Where is the camera located? Does it have direct sunlight, could it be over heating in the afternoon?
What type of camera is it? IP/POE or HDCIV?
POE:
1. On the camera's web login, is there any reboot scheduled?
2. Is this an NVR with many cameras connected to it's POE switch - Is the power limit of the POE switch almost at max?
HDCVI:
1. Is the camera's power supply alright? Does it over heat around the afternoon each day?
2. Is there any device next to the cable that could interfere with the signal? Microwave for example.