How to fix an error loading a WordPress theme?

Question

Debian

Good day.
There was a problem, maybe someone has already encountered.
Installed WordPress on VDS, when trying to load a large theme, a message appears:
"Are you sure you want to do this? Please try again."
And so in a circle. Small, simple themes load fine, but large ones don't.
I tried to put the same topic on the simplest hosting tariff, everything works. What is the reason, I just can not understand. I read a lot of things on Google, nothing helps (
I would be grateful for help in this matter.

Answer 1

Are you sure you want to do this?