But... a driver can become fouled, in which case you need to load them again. The latest will be on the website.
Correct me if I'm wrong.... but that's what my addled brain remembers.

This is after checking cables/connections/ and if the card is seated properly.
If it's none of these then the monitor is already going bad. The blue driver on the monitor board is futzing up. RGB minus blue leaves Red (pinkish color) and Green.