Error "you must have the Connect permission...you are logged in as Guest"

Issue

On Tableau Server, when you try to open views connected to published data sources, one of the following errors might occur:

Forbidden Action

To access this workbook, you must have the Connect permission for its data sources. Because you are logged in as Guest, you do not have this permission. Log in as a named user to try again

HTTP 403
ERROR
Access Denied
Access Denied by security policy

In addition, when you try to publish a workbook that is connected to a published data source, the following error might occur:

An error occurred while publishing. Internal server error.

Environment

Tableau Server
Distributed environment
Tableau Server Data Connection
Forward (Internet) Proxy
User has Connect permissions

Resolution

Work with your IT team to ensure that outgoing connections from all computers running Tableau Server always bypass the Forward (Internet) Proxy when going to the following addresses:

IP addresses of all computers running Tableau Server
Host names of all computers running Tableau Server
localhost

The exact steps required to resolve this issue will vary depending on the environment. If the Forward Proxy is manually configured on the computers running Tableau Server, the following steps might apply:

Use the Tableau Server Run As User account to sign in to Windows on the computer running Tableau Server, and then open Internet Explorer. For more information, see Run As User in Tableau Help.
In Internet Explorer, select Tools > Internet options.
On the Connections tab, click LAN Settings.
The Use a proxy server for your LAN check box should be selected. If this check box is not selected, you are not using a proxy and the issue in this article does not apply.
Click Advanced.
In the Exceptions field, add localhost and the IP addresses of all computers in the Tableau Server distributed environment, and then click OK three times.
Restart Tableau Server.

Cause

This error occurs because of the environmental configurations that are external to Tableau Server.

Tableau Server internal communications are being redirected through a Forward (Internet) Proxy, which requires authentication. Distributed installations of Tableau Server require direct connections between computers.