I am afraid that I see no template.c4d:

However, I think I have some idea…
In fact, I have a dual monitor set-up + two 1080Ti,
and as far as I know, the OpenGL setting in C4D preference shows only 1 of my GPU,
what I have just found that if the c4d comes on my 1st monitor (GPU 1) after booting up, the viewport is fine.
but when it boots up on my 2st monitor (GPU 2), it greyed out, and I grad my C4D window to my 1st monitor, the viewport will then be normal again, no matter where I drag it to.
Do you think it is the fix..? or am I understanding it wrong.