Ubuntu: import OSM to PostgreSQL: Database server failed to load /srv/

I am trying to setup a Nominatim server following this tutorial:

Shortly after I run the import using the following command:

/srv/nominatim/build$ /srv/nominatim/build/utils/setup.php --osm-file /home/zineb/data/great-britain-latest.osm.pbf --all 2>&1 | tee setup.log

I get the following error:

2022-03-02 11:49:27 == module path: /srv/nominatim/build/module
2022-03-02 11:49:27 == Create DB
2022-03-02 11:49:27 == Setup DB
Postgres version found: 12
Postgis version found: 3.2
PHP Fatal error: Uncaught Nominatim\DatabaseError: [500]: Database server failed to load /srv/nominatim/build/module/nominatim.so module thrown in /srv/nominatim/Nominatim-3.5.1/lib/DB.php on line 61

What can be the source of this issue?

Thanks in advance.