Vertical Elastic Query is not identifying Object I did create an External Datasource, identical to the guide described here https://www.sqlservercentral.com/articles/cross-database-queries-in-azure-sql-database .The process is pretty simple, so just for illustration.
CREATE MASTER KEY ENCRYPTION ...
CREATE DATABASE SCOPED CREDENTIAL ...

CREATE LOGIN &lt;externaldbname&gt; WITH PASSWORD = '&lt;somepassword1&gt;'; 
CREATE USER externaldbname FOR LOGIN externaldbname;

CREATE USER externaldbname FOR LOGIN externaldbname;

CREATE EXTERNAL DATA SOURCE ...
CREATE EXTERNAL TABLE ..

All executed successfully. Now when I try to select something from the external database, this error is raised

Msg 46823, Level 16, State 1, Line 3
Error retrieving data from sar*****.database.windows.net.carDB.  The underlying error message received was: 'Invalid object name 'SalesLT.Addresstest'.'.

I didn't get the error msg as the method I followed is used/shown in multiple website and tutorials.
It looks permissions/authentication related to me.
Assuming that the 2 databases are on the same logical server, then your checklist of things to validate:
There is a login in the master database named 
There is a user in the &quot;carDB&quot; database named  mapped to the login
The SalesLT.Addresstest table exists in carDB
The user  in carDB has SELECT permissions on the SalesLT.Addresstest table
Test the above by connecting to carDB as the user and selecting from SalesLT.addresstest
There is a MASTER KEY created in the database that you are querying from
There is a CREDENTIAL in the database that you are querying from whose identity matches
the LOGIN that was created - same name and password.
The EXTERNAL DATA SOURCE is created in the database you are querying from
The EXTERNAL TABLE is created in the database you are querying from and matches the schema of SalesLT.Addresstest