Error while opening Applications tab in Plesk: ERROR: Call to a member function getWordPress() on null (Instances.php:152)

Symptoms

1. The following error message is shown on an attempt to enter Domains > example.com > Applications:

   CONFIG_TEXT: ERROR: Call to a member function getWordPress() on null (Instances.php:152)

2. The following SQL query can be found with enabled debug in /var/log/plesk/panel.log:

   CONFIG_TEXT: DEBUG [dbquery] [135] SQL: SELECT `smb_apsInstances`.* FROM `smb_apsInstances` AS `smb_apsInstances` WHERE (`registryResourceId` = '0b52b2e3-f878-4535-aa39-f422e47df05d')
   DEBUG [dbquery] [135] END: 0.00022602081298828 sec
   PHP Fatal error: Call to a member function getWordPress() on null in /usr/local/psa/admin/plib/Smb/View/List/App/Instances.php on line 152

3. registryResourceId from the query in step 2 is missing in the table smb_apsInstances :

   # plesk db "select * from smb_apsInstances where 'registryResourceId' = '0b52b2e3-f878-4535-aa39-f422e47df05d';"
   Empty set (0.00 sec)

Cause

Database inconsistency in regards to WordPress application.

Resolution

1. Connect to the server via SSH.

2. Create a backup of psa and apsc databases :

   # mysqldump psa -uadmin -p`cat /etc/psa/.psa.shadow` > psa_current.sql

   # mysqldump apsc -uadmin -p`cat /etc/psa/.psa.shadow` > apsc_current.sql

3. Check that registryResourceId from the error message exists in apsc database:

   # plesk db

   MYSQL_LIN: select * from apsc.aps_registry_object where uid='0b52b2e3-f878-4535-aa39-f422e47df05d';
   +----+--------------------------------------+--------------+---------------------+---------+
   | id | uid | type | creation_time | enabled |
   +----+--------------------------------------+--------------+---------------------+---------+
   | 3 | 0b52b2e3-f878-4535-aa39-f422e47df05d | aps.resource | 2020-01-14 02:42:42 | y |
   +----+--------------------------------------+--------------+---------------------+---------+

   If this query returns empty set, refer to the following article: APSC inconsistency: Cannot find registry resource for Application ID

4. Check that affected domain is presented in apsContexts table:

   MYSQL_LIN: select id from domains where name='example.com';
   +----+
   | id |
   +----+
   | 1 |
   +----+

   MYSQL_LIN: select * from psa.apsContexts where pleskId=1;
   +----+-----------+---------+-------+----------------+
   | id | pleskType | pleskId | ssl | subscriptionId |
   +----+-----------+---------+-------+----------------+
   | 1 | hosting | 1 | false | 1 |
   +----+-----------+---------+-------+----------------+ |

5. Find all required values to insert:

   MYSQL_LIN: select id from smb_apsPackages where vendor like '%WordPress%';
   +----+
   | id |
   +----+
   | 2 |
   +----+

   MYSQL_LIN: select id as parentContextID from smb_apsContexts where packageId=2 and contextType=0;
   +-----------------+
   | parentContextID |
   +-----------------+
   | 3 |
   +-----------------+

   MYSQL_LIN: mysql> select id as ContextID from smb_apsContexts where packageId=2 and contextType=1;
   +-----------+
   | ContextID |
   +-----------+
   | 4 |
   +-----------+

6. Get registryResourceId from the error message and insert correct value into smb_apsInstances:

   MYSQL_LIN: mysql> insert into smb_apsInstances (parentContextId,contextId,metaId,registryResourceId) values (3,4,1,'0b52b2e3-f878-4535-aa39-f422e47df05d');