No ability to save/preview/publish the posts

Hello,

Could you please support me on the issue below:
Recently, I faced with the issues during working on post article.
When I’m editing a piece or article, the “WP-Admin times out” and you cannot save draft or publish a draft. (Link for screenshot in attachment https://drive.google.com/file/d/1_lhXSD8wib5aYU4WLXQCQefVESyqO0vJ/view ).
The save/preview and publish the draft.
But if you take a look at the dev tool you will see that server is responding.

Additional information
1) The issue happens from time to time ( could appear once in a week and then appear 2 times in 30 mins)
2) I tried to check the conflict plugins but checking 8 hours in a row did not give the results ( issue did not appear)
3) The issue starts to appear on WP version 4.9.5 and continuing on WP version 4.9.7

Thank you in advance for your support!