Unable to start Plesk Premium Antivirus in Plesk: Plesk authorization failed: HTTP request error [35]

Symptoms

• Attempt to start Plesk Premium Antivirus at Tools & Settings > Services Management > Plesk Premium Antivirus fails with the following error message:

  Unable to manage service by drwebmng: ('start', 'drweb'). Error: /usr/local/psa/admin/bin/drwebmng[24410]: Unable to start drweb antivirus daemon

• When starting Plesk Premium Antivirus via a command-line interface, the operation fails with:

  # service drwebd start
  Restarting Dr.Web drwebd...
  ...
  Plesk authorization failed: HTTP request error [35]
  Error: Plesk Software not running.

• SSL ciphers defined in /etc/sw-cp-server/conf.d/ssl.conf differ from the output below:

  # grep ssl_ciphers /etc/sw-cp-server/conf.d/ssl.conf
  ssl_ciphers EECDH+AESGCM+AES128:EECDH+AESGCM+AES256:EECDH+CHACHA20:EDH+AESGCM+AES128:EDH+AESGCM+AES256:EDH+CHACHA20:EECDH+SHA256+AES128:EECDH+SHA384+AES256:EDH+SHA256+AES128:EDH+SHA256+AES256:EECDH+SHA1+AES128:EECDH+SHA1+AES256:EDH+SHA1+AES128:EDH+SHA1+AES256:EECDH+HIGH:EDH+HIGH:AESGCM+AES128:AESGCM+AES256:CHACHA20:SHA256+AES128:SHA256+AES256:SHA1+AES128:SHA1+AES256:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK:!KRB5:!aECDH;

Cause

Custom ssl_ciphers are defined in /etc/sw-cp-server/conf.d/ssl.conf.

Resolution

1. Connect to the Plesk server via SSH.

2. Create a backup of the file
/etc/sw-cp-server/conf.d/ssl.conf:

   # cp -pr /etc/sw-cp-server/conf.d/ssl.conf /etc/sw-cp-server/conf.d/ssl.conf.back

3. Open the file
/etc/sw-cp-server/conf.d/ssl.conf in a text editor. In this example, we are using the vi editor:

   # vi /etc/sw-cp-server/conf.d/ssl.conf

4. Find the line with ssl_ciphers and change its value to:

   ssl_ciphers EECDH+AESGCM+AES128:EECDH+AESGCM+AES256:EECDH+CHACHA20:EDH+AESGCM+AES128:EDH+AESGCM+AES256:EDH+CHACHA20:EECDH+SHA256+AES128:EECDH+SHA384+AES256:EDH+SHA256+AES128:EDH+SHA256+AES256:EECDH+SHA1+AES128:EECDH+SHA1+AES256:EDH+SHA1+AES128:EDH+SHA1+AES256:EECDH+HIGH:EDH+HIGH:AESGCM+AES128:AESGCM+AES256:CHACHA20:SHA256+AES128:SHA256+AES256:SHA1+AES128:SHA1+AES256:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!3DES:!MD5:!PSK:!KRB5:!aECDH;

5. Save the changes and close the file.

6. Restart
sw-cp-server and
drwebd services:

   # service sw-cp-server restart

   # service drwebd start