The WP Toolkit window shows a scan in progress despite not running

Symptoms

The WP Toolkit window will show 0% completion when checking the security of WordPress installations, Checking for updates, and or Scanning for WordPress websites, as shown in the following image. 

Description

The WP Toolkit User Interface shows that it is scanning, but checking the SQLite database shows that none of these processes have actually started. 

[ root@server ~]# sqlite3 /usr/local/cpanel/3rdparty/wp-toolkit/var/wp-toolkit.sqlite3
SQLite version 3.32.3 2020-06-18 14:00:33
Enter ".help" for usage hints.
sqlite> SELECT * FROM LongTasks WHERE status='not_started';
265|cpanel-scan-new-instances|not_started|0
266|mass-check-updates|not_started|0
267|mass-security-operation|not_started|0
sqlite> .quit

Workaround

Check to see if the wp-toolkit-background-tasks service is running. 

[root@server ~]# service wp-toolkit-background-tasks status
Redirecting to /bin/systemctl status wp-toolkit-background-tasks.service
● wp-toolkit-background-tasks.service - Background tasks executor for WP Toolkit
   Loaded: loaded (/usr/lib/systemd/system/wp-toolkit-background-tasks.service; enabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Fri 2021-01-29 10:47:01 UTC; 5 days ago
 Main PID: 14447 (code=killed, signal=KILL)
Jan 29 10:47:01 cloud.server.tld systemd[1]: wp-toolkit-background-tasks.service: main process exited, code=killed, status=9/KILL
Jan 29 10:47:01 cloud.server.tld systemd[1]: Unit wp-toolkit-background-tasks.service entered failed state.
Jan 29 10:47:01 cloud.server.tld systemd[1]: wp-toolkit-background-tasks.service failed.
Jan 29 10:47:01 cloud.server.tld systemd[1]: wp-toolkit-background-tasks.service holdoff time over, scheduling restart.
Jan 29 10:47:01 cloud.server.tld systemd[1]: Stopped Background tasks executor for WP Toolkit.
Jan 29 10:47:01 cloud.server.tld systemd[1]: start request repeated too quickly for wp-toolkit-background-tasks.service
Jan 29 10:47:01 cloud.server.tld systemd[1]: Failed to start Background tasks executor for WP Toolkit.
Jan 29 10:47:01 cloud.server.tld systemd[1]: Unit wp-toolkit-background-tasks.service entered failed state.
Jan 29 10:47:01 cloud.server.tld systemd[1]: wp-toolkit-background-tasks.service failed.

If this is showing as down, you'll need to restart the service. 

[root@server ~]# service wp-toolkit-background-tasks start
Redirecting to /bin/systemctl start wp-toolkit-background-tasks.service

Once the service has been restarted, verify that the service is up and running. 

[root@server ~]# service wp-toolkit-background-tasks status
Redirecting to /bin/systemctl status wp-toolkit-background-tasks.service
● wp-toolkit-background-tasks.service - Background tasks executor for WP Toolkit
   Loaded: loaded (/usr/lib/systemd/system/wp-toolkit-background-tasks.service; enabled; vendor preset: disabled)
   Active: active (running) since Thu 2021-02-04 08:46:21 UTC; 10s ago
 Main PID: 6113 (run-script)
   CGroup: /system.slice/wp-toolkit-background-tasks.service
           ├─6113 /usr/bin/sw-engine /usr/local/cpanel/3rdparty/wp-toolkit/bin/run-script background-tasks-executor.php
           └─6116 /usr/bin/sw-engine /usr/local/cpanel/3rdparty/wp-toolkit/bin/run-script execute-background-task.php 268Feb 04 08:46:31 cloud.server.tld sudo[6221]: wp-toolkit : TTY=unknown ; PWD=/usr/local/cpanel/3rdparty/wp-toolkit/scripts ; USER=root ; COMMAND=/bin/sh -c find /home/cpuser...rintf '%h\0'
Feb 04 08:46:31 cloud.eja-webdesign.nl sudo[6224]: wp-toolkit : TTY=unknown ; PWD=/usr/local/cpanel/3rdparty/wp-toolkit/scripts ; USER=root ; COMMAND=/bin/sh -c find /home/cpuser/ad...rintf '%h\0'