Forgot the NPrinting's postgres superuser password - password authentication failed for user "postgres"?

[Andre_Sostizzo]

The NPrinting's postgres superuser password was forgotten/not recorded and cannot perform a backup/restore, or connect to the database using PGAdmin. The admin tool may be located under the following path on newest builds C:\Program Files\NPrintingServer\pgsql\pgAdmin 4\bin\pgAdmin4.exe. More information under Installing and Configuring PGAdmin 4 to access the PostgreSQL database used by Qlik Sense or NPrinti...

When attempting to run the Qlik.NPrinting.Manager.exe backup command the following message is displayed:
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Manager has stopped working
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The following is registered to the nprinting_manager.log stored in the default NPrinting logs folder:
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Qlik.NPrinting.Repo 19.0.4.0 Qlik.NPrinting.Repo.Utils.NHibernateUtils 20190430T101505.536-04:00 ERROR DH6607 0 0 0 0 0 0 0 0 The database nprinting could not be queried. Npgsql.PostgresException: 28P01: password authentication failed for user "postgres"? at Npgsql.NpgsqlConnector.d__157.MoveNext()?--- End of stack trace from previous location
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Unhandled Exception: Npgsql.PostgresException: 28P01: password authentication failed for user "postgres"
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Environment:

• Qlik NPrinting 

Resolution:

The postgres super user password may be reset manually by a side procedure similar (not the same; see below*) to what is documented under the Qlik Sense article How-to reset forgotten PostgreSQL password in Qlik Sense. Then a backup may be generated. However, then NPrinting services will not know of the password change and will not be able to connect to the database. Making the change requires a NPrinting Server reinstall in order to set the encrypted postgres superuser password accordingly.

The best approach here would be to perform a version upgrade in order to automatically generate a database backup which is placed under C:\ProgramData\NPrinting.

After the upgrade, a complete re-install of NPrinting Server current version (not the upgrade version) is required to reset the password. After that the database backup can be restored. How to BackUp and Restore NPrinting Repository Database from End to End

If you are already on the latest version, and cannot restore a backup that was generated automatically either because the backup is too old or there was never an upgrade, the similar procedure (for Qlik Sense) mentioned above can be performed but there is no tool for pointing services to the database using the new password. A reinstall of NPrinting will still be necessary.

* pg_hba.conf and psql.exe are not placed in the same location;
the postgres database service is called "QlikNPrintingRepoService";
database tcp port is 4992 by default;
Please contact Qlik Support for assistance if needed.