Drive disappears. File Explorer closes while using file

Win v.1903. I have 2 3tb external drives and 1 1tb internal drive and the main drive is a 500gb ssd. My internal drive normally won't show up in file explorer. Not sure why. Recently it started showing up but when I try to play a video file on it using VLC(same issue with different video players), the file plays for a bit then closes. File explorer closes also and when I reopen it, the internal drive is gone. If I reboot the pc, the drive shows up again. I thought maybe the pc couldn't handle all the drives but I disconnected one of the external drives, rebooted and tried again. The same thing happened. Any ideas? Let me know if more information is needed.

install hard disk sentinel and crystaldiskinfo. these 2 programs are for testing hard disk health. run both and see if they detect the 1tb disk and if it is detected then check the hard disk health

Thanks for responding. Hard Disk Sentinel shows the message below. It also said the drive was fine. I guess I need to check my connections. It is odd that it shows up when I reboot.

Problems occurred between the communication of the disk and the host 81 times.
In case of sudden system crash, reboot, blue-screen-of-death, inaccessible file(s)/folder(s), it is recommended to verify data and power cables, connections - and if possible try different cables to prevent further problems.
More information: Hard disk case: communication errors

No actions needed.

The cable from HDD dont make good contact. Remove it and reinsert it or replace it.

That seems to have fixed it. Thanks so much for your help.