Your user needs to have the necessary permission to download AL symbols from Visual Studio Code (VSCode), else you will end up with "Could not download symbols" error in VS Code.

In order to download symbols, User needs to have SUPER permission or should have "D365 EXTENSION MGT" permission assigned. Symbols are stored per tenant and not per company, therefore Company field must be blank in either option.

Clear credentials cache in VSCode and sign in again from VS Code (Download symbols and it will ask your credentials to sign in) 
once you have the "D365 EXTENSION MGT" permission group or SUPER permission set assigned to the user, 
This time VSCode will successfully download symbols from Microsoft Dynamics 365 Business Central.


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Thank you and Regards,
Tharanga Chandrasekara