This solved my problem. https://wordpress.org/support/topic/cannot-create-new-post-or-page/ I noticed the only change I made after migrating the hosting company was PHP 5.6 to 7. The other 8 WordPress sites did not have this problem. For now, reverted and it works. Upgrade soon.
Shuting readying to release the balloons, a new beginning.
good day with this pic to launch the new website look. pink pink pink!