How To Fix FatalError: pgAdmin 4, the application server could not be contacted

PostgreSQL recently released version 15. Now the pgAdmin comes as a desktop application instead of being opened in a browser. But they have recently been an error that’s roaming around which reads ‘pgAdmin 4 the application server could not be contacted.’ I have to admit, I do not fully know what the causes of this error are (all I know is it has to do with servers) but I’ve also encountered this error myself, and luckily, I found a quick way to fix it, but it might not be the best. I’m going to share with you in this blog post how o did it. Feel free to let me know in the comments if there are any other better fixes.

Here are the steps to take in order to fix the fatal error:

1. Click the configure button at the bottom right corner.
2. check the checkbox which reads, Fixed port number.
3. Change the port number to the one you entered during the installation
4. click the save button at the bottom right corner of the window.

Now here are details steps:

1. Click the configure button at the bottom right corner.

On the error window, click the configure button at the bottom right corner of the error window.

2. check the checkbox which reads, Fixed port number.

After you click the Configure window, another window will pop up. On this window, check the checkbox which reads, Fixed port number.

3. Change the port number to the one you entered during installation

Clicking the checkbox will enable the port input on the right side. Change the port number to the one you entered during installation, if you used our guide on how to connect PostgreSQL with Django, it’s more likely you’ve used port 5432 because it is the default. If a message that says ‘the port is already in usage pops up’, keep on changing it till you find a port that is free.

4. Click the save button at the bottom right corner of the window.

After changing the port number, click the save button at the bottom right corner of the window.

A window will pop up telling you that pgAdmin has to be restarted in order to apply the changes. Go ahead and click the ‘okay’ button.

And wait for the app to start. Most of the time, it might not restart on its own, so if it takes a long time before it starts, better do that on your own.

Okay, above is what I did to fix the error. Please let me know in the comments section below if you have any other ways of fixing the error. Peace.