Plesk domains and various actions like updating WordPress plugins do not work under CentOS 7: cURL error 77

Symptoms

• Domains on Plesk server display Error 500 and the following error message is output to the logs:

  PHP Fatal error: Uncaught GuzzleHttpRingExceptionRingException: cURL error 77

• Various actions in Plesk fail, including:
     - Issuing or updating Let's Encrypt certificates
     - Installing or updating WordPress plugins
     - Updating licenses
     - Authentication via Google
     - Installing new extensions from extension catalog
  And one or more of the following messages are displayed:

  Error 500

  Error: Could not get Mozilla tls config: cURL error 77: (see https://curl.haxx.se/libcurl/c/libcurl-errors.html)

  Unable to initialize NSS: -8023 (SEC_ERROR_PKCS11_DEVICE_ERROR)

Cause

Recent CentOS 7 update of NSS packages.

Resolution

1. Connect to the server via SSH

2. Restart all the PHP services including Plesk:

   # systemctl restart plesk-php* && systemctl restart sw-engine

   Note: if Litespeed is installed, it is required to restart it as well:

   # systemctl restart lscgid