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Tech Tip: "Unable to connect to the Web server. Your 4D license number..." Error on Browser
Published On: January 17, 2024

If you get the following error on the web browser...

Unable to connect to the Web server. Your 4D license number doesn't allow you to connect to the Web server from an IP address different from the server. may be encountering one of the following scenarios.

Scenario 1 - 4D Standalone
If you are running the web server on 4D Standalone, a second web client is attempting to connect to the web server. The 4D developer license only allows one web connection from a different IP address. A local web connection from the same machine does not count.

Scenario 2 - Hosting the web server on 4D Server
When hosting a web server on 4D Server, a 4D Web Application Expansion License is needed to allow web connections from different IP addresses. You can check for this by going to the License Manager window (in 4D, go to Help > License Manager...). If you do not have this, you may contact your account representative to purchase this expansion license.

Scenario 3 - Hosting the web server on 4D Client
There are a few things to troubleshoot with this kind of configuration.

  1. Similar to the previous scenario, first check that you have the 4D Web Application Expansion License for 4D Client. This is also done by checking the License Manager window on 4D Server. If you are hosting multiple web servers on multiple 4D clients, make sure that you have enough expansion licenses for each machine; each license can only be used with each 4D instance. Again, you may speak with your sales representative to ensure your licenses are in order.

  2. Then, check to make sure you are logging in with a user that has access to the expansion license.

    • If there are no specific users with custom access (via Users and Groups), the expansion licenses are consumed on a first come first serve basis. In this case, you must make sure that the 4D client you intend to host the web server logs in first to consume the web application expansion license.

    • If a specific user has custom access, the 4D client login order does not matter.

  3. The next thing to check with this configuration is ensuring that the default login dialog is being used. A custom login dialog that logs in with a default user and changes users with the CHANGE CURRENT USER command will not work. When changing between users with different license accesses, CHANGE CURRENT USER does not release the licenses from the previous user/does not consume the licenses of the new user. In short, a custom login will only result in the same browser error.