topic Re: installing Experience Builder SDK npm start error 4091 in ArcGIS Experience Builder Questions

installing Experience Builder SDK npm start error 4091

LoriEmersonKDOT — Fri, 27 Jun 2025 14:32:20 GMT

So, I installed Experience Builder SDK successfully on our production portal, but then tried to move it to our test portal.

I've been able to change the "https://localhost:3001/" to use the Client ID from the Experience Builder credentials on the test portal. (Note: I have already deleted the Experience Builder Credentials from the production portal.)

However, when I try npm start from the windows command prompt, I get the EADDRINUSE error, errno -4091 on port 3000.

I tried:

netstat -ano -p tcp |find "3000"

taskkill /F /PID <PID>

where <PID> is the far-right number from the netstat command, as described in this post: https://community.esri.com/t5/arcgis-experience-builder-questions/arcgis-experience-builder-uninstall/td-p/1372364

However, I still get the same error. Any advice on how to uninstall and reinstall Experience Builder SDK?

Re: installing Experience Builder SDK npm start error 4091

JunshanLiu — Mon, 30 Jun 2025 00:50:28 GMT

Are you running two Experience Builder servers? You don't need to uninstall the ExB, you can just stop one and start another one.

Re: installing Experience Builder SDK npm start error 4091

LoriEmersonKDOT — Mon, 30 Jun 2025 20:22:43 GMT

I just have the Experience Builder installed one place on my C: drive, with the server folder and client folder. How could I run two servers? Do I not need to run the "npm start" command from the server folder?