Error importing database: Could not import package

 If you find this error when importing a .bacpac package to your SQL Server pay attention to the way you are authenticating your connection to SQL Server, even if you are connected into the SQL instance server.

Your line of connection must have this additional parameter:

/TargetTrustServerCertificate:True

Example: SqlPackage.exe /a:import /sf:c:\temp\backup.bacpac /tsn:localhost /targetTrustServerCertificate:True /tdn:AxDBN /p:CommandTimeout=600

If you want to know more about it, go to this place:

https://techcommunity.microsoft.com/t5/azure-sql-blog/connection-security-improvements-in-sqlpackage-161/ba-p/3672758