Why the error occurs - update error. Is the response not a valid JSON response?

Question

PHP

Problem with wordpress. On the local everything works fine, after transferring to the host, this error occurs when the page is updated, while everything is ok in the records. Plz tell me how can I fix this?
The line from the log with the error:

2020/07/13 23:10:25 [error] 24811#24811: *86294652 openat() "/var/www/u110586/data/www/testing.ru//wp-json/wp/v2/pages/373" failed (2: No such file or directory), client: 85.173.126.103, server: testing.ru, request: "POST /wp-json/wp/v2/pages/373?_locale=user HTTP/1.1", host: "u110586.com4.ru", referrer: "http://u110586.com4.ru/wp-admin/post.php?post=373&action=edit"

Answer 1

I suspect that the error is in two slashes //after the site name:

var/www/u110586/data/www/testing.ru//wp-json/wp/v2/pages/373