I found the solution.
We loaded the wrong virtualenv enviroment.
--
View this message in context: http://www.postgresql-archive.org/pgadmin4-1-6-python-wheel-doesn-t-work-under-Ubuntu-Server-16-04-LTS-tp5971865p5972330.html
Sent from the PostgreSQL - pgadmin support mailing list archive at Nabble.com.