Fixed-Cannot Connect to App Store on Mac (Mojave/High Sierra)

After upgrading the Mac system to MacOS Mojave, many users cannot log in to the App Store and got an error message "Cannot Connect to App Store". This stops users from downloading applications from the Mac App Store, so it's very inconvenient. This article is to help you the "cannot connect to App Store" on Mojave, High Sierra and more. Here are five ways for you to work out the issue.

1. Check Network Connection

If you encounter the "Cannot connect to the App Store" error message, your internet connection may be the culprit. So it's better to check network connection first. Follow the instructions below to see whether internet connection is working on your Mac.

Step 1. Click on the Apple logo > System Preferences > Network.
Step 2. If there is a red icon in front of the network you are connected to, the network is not working. That's why you can't connect to App Store on Mac.

2. Switch to Apple's global DNS address

Using Apple's DNS address may help to solve that "cannot connect to App Store" error.

Step 1. Open System Preferences > Network. click Advanced.
Step 2. Click Advanced > DNS.
Step 3. Click on + under the DNS Servers box and add the DNS address: 8.8.8.8
Step 4. Click on + again to add another Apple's global DNS address: 8.8.4.4
Step 5. Click on OK. Restart your Mac.

After restarting the Mac, open App Store and see if you can install apps without the "cannot connect to App Store" error.

3. Delete invalid or incorrect certificates

Step 1. Click on Go. Click on Go to Folder in the contextual menu.
Step 2. Type the following path into the Go window: /var/db/crls/
Step 3.  In the window that open, find two files: cricache.db and ocspcache.db and delete them.

Now Restart your Mac and check to see whether it can connect to App Store now.

4. Edit KeyChain certificates

The KeyChain application contains passwords and certificates of Mac App Store. If the certificates of App Store is corrupted, you "cannot connect to the App Store" . You can try to edit certain certificates for App Store in the KeyChain application to resolve the problem.

Step 1. Go to Applications > Utilities > KeyChain Access.
Step 2. Under Category, click Certificates.
Step 3. Search Class in the search bar in the top right corner. In the search result, double click the certificate whose icon has a blue outline
Step 4. The information of the certificate will be opened. Click Trust and choose Always Trust for Secure Sockets Layer (SSL).
Step 5. Close the window. Then reopen the window of the certificate. This time, choose Use Custom Settings for When using this certificate. Again close the window.
Step 6. Reconfigure Always Trust for Secure Sockets Layer (SSL) and When using this certificate for other certificates that have an icon with a blue outline.

After the above steps, restart your Mac for the changes to take effect.

5. Edit /Library/Security/Trust Settings with Terminal Command

Note that the following steps will delete your Trust settings. So you may want to go to Library > Settings > Trust and back up the folder on another location.

Step 1. Open Teminal.
Step 2. Enter the line: cd "/Library/Security". Hit Enter key on the keyboard.
Step 3. Perform this line: sudo ditto -ck "Trust Settings" TrustSettingsBackup.zip.
Step 4. After the command lines above, enter the line: cd "/Library/Security/Trust Settings"
Step 5. Finally, enter this line: sudo rm *.plist.

Now close Terminal after finishing the command lines above. Restart your Mac and try to sign into the App Store.

Can you connect to App Store on Mac now? If not, describe your problem below.