Websites & Domains page loads slowly when SEO Toolkit 1.1.15 is enabled on Plesk for Linux

Symptoms

• Log into Plesk or opening the Domains/Websites & Domains page takes a significant amount of time and Extensions > SEO Toolkit is installed and enabled on the server.

• The following entries are found in /var/log/plesk/panel.log with Plesk debug mode enabled:

  CONFIG_TEXT: DEBUG [extension/xovi] Request to API (POST) https://pleskwebservice.xovi.net/ with payload: {"method":"keymonitor_overview_tableKpis","input":{"topdomain_hashes":["fd9da969-635e-4eac-87b6-1cd364cd3684","e60a2817-7880-4aef-a467-17d53d457d89"]}}
  DEBUG [extension/xovi] Response of API: {"success":false,"message":"no_domains_found"}
  DEBUG [extension/xovi] Communication with API time: 31.038042068481

  ---

  CONFIG_TEXT: DEBUG [extension/xovi] Request to API (POST) https://pleskwebservice.xovi.net/ with payload: {"method":"keymonitor_manage_countKey","input":[]}
  ERR [1] PleskExt\Xovi\Exception\RankTrackerException: ranktracker.exception.used_count_failed

Cause

This is the SEO Toolkit 1.1.15 extension bug with ID XOVI-5564 which has been fixed in 1.1.16 version