A problem with similar symptoms, but apparently different cause was just answered over in the Web AppBuilder for ArcGIS forum. But, my question is specific to the AGOL variant of the Web AppBuilder.
When I add multiple images (a few 20x20 pixel png mini-icons) to the text body of an "About" or "Splash" widget I start to get "Failed to Save App" errors.
- A single icon doesn't cause the problem, only multiple icons.
- I can remove the icons, and am able to save again.
- With the icons in the text body, I can successfully use "Save As", but that becomes inconvenient when you're just making small little tweaks to wording in response colleague's suggestions.
Any ideas? I do not know if this predates the recent update as I hadn't used the icons before the update.