Issue Cannot login to Admin area using the Safari browser...

[Kwasi]

I've always been able to log in to my Plesk Control Panel using the Safari browser.
Done it countless times.

Then all of a sudden this morning for no apparent reason I cannot.

I get this text on an error page:
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Safari Can’t Open the Page

Safari can’t open the page “https://ipaddress:8443” because the server unexpectedly dropped the connection. This sometimes occurs when the server is busy. Wait for a few minutes, and then try again.
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I'm able to log in just fine using the Chrome browser.

I've seen posts elsewhere where others have had similar issues.

Nothing really has been updated on my Macs. Same Safari browser, same OS.
I'm running Sierra on my older iMac and High Sierra on my 2017 MacbookPro.
Same happens on either device.

Thoughts on why all of sudden out of the blue this would start to happen?
Solution?

 

[IgorG]

What about access through https://domain.tld:8443 ? Have you checked related errors in Plesk logs:

• Access log: %plesk_dir%admin\logs\W3SVC<IIS site ID>\ex<date>.log
• PHP errors: %plesk_dir%admin\logs\php_error.log