macOS Sierra. Safari 10.0. App is hanging while loading site or switching tabs I noticed yesterday this weird behavior, don't how to trace it, actually.

The thing is this: When the https://github.com loads I'm seeing spinning circle for about 5 seconds while Safari is hanging.

Additionally: when I open some other tabs, not github, it's okay totally.  When I'm switching to github tab the spinning circle appears again and Safari hanging for about that 5 seconds.

Similar behavior with bitbucket.org.

I've identified only these two sites.  Not sure what they share in common.

I've removed completely all content inside my ~/ regarding Safari data.

Opened Safari totally stock, as the Apple ships, the same issue.

Also tried with removing all website data and cookies -- the same.

Here's the image of loading content:

it kind of loads/hangs for about 5 seconds in that way.

Anyone got the clue, how I trace this maybe, or identify what might be the cause here?  Thanks.

Ivan.
Seems like this an issue with digicert's OCSP and Роскомнадзор. macOS tries to check certificate revocation every time when you change Safari tab with digicert certificate, but IP address is blocked by provider. Same issue with App Store downloads.

I've added different IP address to the /etc/hosts:

72.21.91.29 ocsp.digicert.com

and everything works fine for me now.

Also you can try other solutions or check details from https://stackoverflow.com/questions/39899002/github-is-painfully-slow-on-safari-macos-sierra-10-12