Cloudflare block admin page log

Hello,
I had an unpleasant surprise with cloudflare this week.
First the site was down with an error 522.
I looked with my hoster. He asked me to reset the original DNS and to put cloudflare off. Miracle my site was accessible again.
I found out later that cloudflare was under maintenance.
I waited 24 hours and then I put cloudflare back on and put the cloudflare DNS back on. The site restarted with some error 522.
Now visitors can see the site but I tried to access the admin console of my site. I tried mywebsite/admin; /login and /wp-login.php. I could not reach. I changed the wp-login.php file and regenerated a .htaccess file. Nothing does it so I can access my admin console. I asked my hoster for help. He advised me again to turn off cloudflare. And boom, it works again.
So I would like to know how to keep cloudflare and have access to my admin console of my wordpress site.
I thank you in advance for your answer
Kings regards