topic Re: Experience Builder brings 'Blank Page' ExB v12.1 in ArcGIS Experience Builder Questions

Experience Builder brings 'Blank Page' ExB v12.1

aperi — Mon, 20 Jul 2026 20:43:17 GMT

Hi all,

I have a base ArcGIS Enterprise 12.1 single machine deployment (Portal, Server, and Data Store on one box). The Portal home page, Map Viewer, and Content all load normally, but when I launch Experience Builder from the app launcher (https://<machine>/portal/apps/experiencebuilder/), the page comes up completely blank. No error message, no spinner, just an empty screen that stays stuck.

What I've tried so far:
- Cleared browser cache and tested in an incognito window and a second browser: same result
- Confirmed the rest of Portal is healthy
Environment:
- ArcGIS Enterprise 12.1, single machine base deployment
- Accessing through the Web Adaptor, currently over HTTP (not yet on HTTPS with a CA-signed cert)

Has anyone else hit a blank Experience Builder page on 12.1? Wondering if this is a known issue with the release, or a resource failing to load. Any pointers on which logs or configs to check would be much appreciated.

Screenshot of the blank page is attached.

Thanks!

Re: Experience Builder brings 'Blank Page' ExB v12.1

Ke_Xu — Tue, 21 Jul 2026 01:48:29 GMT

Hi @aperi,

What error do you see in the browser console? Does the same issue occur when creating other apps, such as an Instant App?

Thanks,

Re: Experience Builder brings 'Blank Page' ExB v12.1

davidround — Thu, 23 Jul 2026 13:57:51 GMT

Yes. Blank screen when launching any experience or template from experience builder. Looking in dev tools it's failing to load some javascript stuff. I can't fix it 😞

Re: Experience Builder brings 'Blank Page' ExB v12.1

Ke_Xu — Fri, 24 Jul 2026 08:21:22 GMT

@davidround, could you please capture the error messages from the browser console? Also, please submit a Support ticket for this issue. Thanks.

Re: Experience Builder brings 'Blank Page' ExB v12.1

davidround — Tue, 28 Jul 2026 06:56:16 GMT

Sure. I have opened a support ticket because I am no further along.

Issue:

ArcGIS Enterprise 12.1 (upgraded from 11.4) Experience Builder is failing for all users. The builder loads but throws client-side JavaScript errors including "Cannot read properties of undefined (reading 'WebMap')" and "Initializing theme manager failed - Cannot read properties of null (reading 'default')", preventing normal use of Experience Builder.

To troubleshoot, I have:

Tested in multiple browsers including InPrivate mode.
Tested with a newly created Portal user.
Performed a Portal for ArcGIS repair installation.
Installed the latest available Portal 12.1 patch (Portal for ArcGIS Security 2026 Update 2 Patch).
Verified Portal is healthy and returning Web Map content successfully through the REST API.
Verified helper services and federation appear healthy.
Checked Portal logs but no corresponding errors are generated when the issue occurs.

The issue affects all users and appears to occur within Experience Builder itself rather than a specific experience. It occurs whenever creating a new experience, loading a template or opening an existing experience.

Re: Experience Builder brings 'Blank Page' ExB v12.1

O_Kantarcioglu_ct — Tue, 04 Aug 2026 11:23:09 GMT

Hi,

I have the exact issue.

I have installed ArcGIS Enterprise 12.1 with Enterprise Builder and when I open the Experience Builder, I see a black screen and nothing comes up on Developer Tools except in console "Load module error. TypeError: can't access property "WebMap", G.ItemTypes is undefined"

I have a working 12.1 deployment on which I installed the components individually and have no issue there.

When I compare the size of both folder in each environments I see that working environment has 400 Mb folder size and the broken environment has 336 MB folder size.

Please let me know how it turns out @aperi

Thanks!

Re: Experience Builder brings 'Blank Page' ExB v12.1

davidround — Fri, 07 Aug 2026 09:07:36 GMT

I have a support ticket to investigate the issue but this might be helpful information @Ke_Xu if the file sizes are different.