SQL Installation error 27502 – 0

Error 27502. Could not connect to Microsoft SQL Server ‘(local)\SQLExpress14’. Invalid authentication specification (0)

[NL] Ongeldige autorisatiegegevens

[FR] Spécification de permission non valide

Solution

1. Click ‘Ok’
2. Cancel the setup
3. Run the Gateway setup again
4. Select existing database instance => the one you just have installed (in the above printscreen : SQLEXPRESS14BS)