The first thing to verify is that you're using a correct URL for the Management Studio. The management URL for RavenDB 2.5 versions is in the form of:
The URL format for RavenDB 3.0 versions is of the form:
An example 2.5 URL is:
And an example 3.0 URL is:
This URL format is different from the connection string URL, even though both URLs contain the API key and the database name.
If you need any further assistance, please contact us at firstname.lastname@example.org.
Do you not see this as a security issue? The API key would be floating around in plain text.