REST API problems & Permalinks change Problem in openlitespeed wordpress

I installed a new website to google cloud VM instance a wordpress with openlitespeed wordpress.
I have two problems when im trying to install redirection plugin i get this msg:
GET POST SyntaxError: Unexpected token < in JSON at position 0
Unexpected token < in JSON at position 0 (SyntaxError)
Your REST API is returning a 404 page. This may be caused by a security plugin, or your server may be misconfigured

The second problem is that when i am changing the permalinks in wordpress section from plain to post name & every page execpt home page returning 404
Please help.
Thanks Kostas
i fixed it guys..
i use sudo service lsws restart and it worked. i dont know why i had this problem but now everything seems to be perfect!

Thank you !