Scan fails in WP Toolkit: Failed to reset cache for the instance #34: Error: This does not seem to be a WordPress installation.

Symptoms

Scan fails in WP Toolkit with the error:

Scanning for WordPress websites was performed with errors:
Subscription "example.com": Failed to reset cache for the instance #34: Error: This does not seem to be a WordPress installation. Pass --path=`path/to/wordpress` or run `wp core download`.

Cause

Information about the WordPress instance exists in WP Toolkit database.

Resolution

1. Connect to the Plesk server via SSH.

2. Create a backup file of the wp-toolkit.sqlite3 database:

   # cp /usr/local/psa/var/modules/wp-toolkit/wp-toolkit.sqlite3 /usr/local/psa/var/modules/wp-toolkit/wp-toolkit.sqlite3.bak

3. Open WP Toolkit database

   # sqlite3 /usr/local/psa/var/modules/wp-toolkit/wp-toolkit.sqlite3

4. Remove the orphaned records using the instance ID from the error message:

   sqlite> .headers on

   sqlite> delete from instanceProperties where instanceId = 34;

   sqlite> delete from instances where instances.id = 34;

   sqlite> .quit