"Media Offline" error in red background

Hi,
I'm new user of DaVinci Resolve 19. I tried importing my video clips by providing my directory of the same. A few videos loaded nice and correctly, but a few (majority of those, in fact) others are showing a message "Media Offline" with a red background. There is a small "i" button, and I see a proper information , which shows the resolution and codec information of the video clip. But the clip itself is not shown.
Could I get some help on this?
Please see the attachment to know what I see as an information when I hover my mouse near "i".
I'm new user of DaVinci Resolve 19. I tried importing my video clips by providing my directory of the same. A few videos loaded nice and correctly, but a few (majority of those, in fact) others are showing a message "Media Offline" with a red background. There is a small "i" button, and I see a proper information , which shows the resolution and codec information of the video clip. But the clip itself is not shown.
Could I get some help on this?
Please see the attachment to know what I see as an information when I hover my mouse near "i".