For some reason app store simply does not work:
- reset NVRAM;
- remove com.apple.appstore.plist, com.apple.storeagent.plist and then restart,
did not solve the problem.
Does anyone know other possible solutions?
TLDR: If you can browse the web with Firefox or Chrome, but not with Safari, then adjusting your network settings might fix both Safari and the App Store. Start by looking at proxy settings.
I'm hoping you found a solution by now. Just in case this helps anyone, I'm going to share what worked for me. I had no problem browsing the web with Firefox or Chrome, but the App Store just showed a grey window like the screenshot in the original post.
During troubleshooting, I discovered that Safari couldn't connect to any web servers. This suggested that the problem had something to do with the Mac's network settings. I opened the network settings, selected my network adapter, clicked Advanced, went to the Proxies tab, and unchecked Automatic Proxy Configuration. That fixed everything.
Here is a tutorial from a guy who fixed what seems like the same issue you are experiencing:
Check this out
I also recommend you change your time zone to anywhere but your current location, restarting and then choosing "Set time zone automatically using current location" (Date & Time Preferences). Many times this resolved a few Mac OS (X) issues for me.
Let me know how you go.
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