Can’t write post, when click on write page goes blank.

Hi there
I’ve looked through earlier problems about not being able to write posts but no one seems to have answered them.

When I click on ‘write post’ or write page’, although the correct http address appears in the browser the page goes completely blank. I’ve tried it on a number of occasions over a few days and still cannot manage to write a post. This is extremely frustrating as I work on a really busy news website.

Everything else works absolutely fine.

Would really appreciate your input asap.

Cheers
Linda