403 Error Occurs When Attempting to Log In to Administration Screen with CloudFront+Wordpress

I've experienced a few things that I can't put into the management screen.It used to be white.
This time it's 403, so it feels like the connection to the management screen has been cut off by the server.
For lolipop servers, access to Wordpress management screens is restricted by IP.In addition, the Sakura server is set to limit access from overseas by default.
I'm not sure because it's CloudFront, but if it's Amazon, you might want to check the WAF settings.Once you turn off all the firewalls, turn them on one at a time to determine the cause.
Also, .htaccess at /wp-admin/ may be restricted by IP etc.You can set this up with plug-ins such as siteguard.You may want to take a peek.

By the way, it may not matter this time, but just in case.
When a redirect loop error occurs on the administration screen, it usually occurs when the URL in the DB is different from the URL in which it is accessed.
·Not SSL https
·Forgot to turn on www
and so on. You should check the DB URL.However, it is dangerous to cure it directly.Be careful not to back up or serialize.
For redirect loops, this is helpful.
https://wordpress.stackexchange.com/questions/175728/redirect-loop-only-for-multisite-network-admin