Error while Connect to a PostgreSQL database from Power BI Service

I get this error when setting up a new datasource to PostgreSQL in my Gateway in the Service:

"Unable to connect: We encountered an error while trying to connect to . Details: "We could not register this data source for any gateway instances within this cluster. Please find more details below about specific errors for each gateway instance.
Status code: 400
Error Code: DMTS_PublishDatasourceToClusterErrorCode
p-gateway: Unable to connect to the data source undefined.
Underlying error message: Please install Npgsql version 4.0.10.0 or earlier."

I installed the Npgsql 4.0.10 with NpgSQL GAC installation,and reboot the machine ,but it still doesn't work when connectting to  gateway and postgreSQL. Please let me know if you have any solutions

I did install Npgsql 4.0.10.0, restarted everything but it doesn't work.