blank page wp-admin login page

You did not edit any file?

You can resort to https://codex.www.ads-software.com/Common_WordPress_Errors. 95% of the time, I have found that the solutions there have worked.

Just a heads up. the main cause for me most of the time is whitespace before the opening PHP tag </php or using a closing PHP tag ?> at the end of a config file or the functions.php file

I didn’t edit any file at all. no space anywhere. What should I do?

If you visit the login page directly is it blank?
https://www.mysite.com/wp-login.php

Yes. It shows only a white page

Check out your server error logs. They will tell you if and where an error is happening.

Where do you mean? How can I do this?

If you have CPanel or a control panel for your hosting, you may find it there. If you do not have access, you will have to get in touch with your hosting provider and get the logs from them.