Everything is shared with Everyone (Public). Why am I and my clients still getting a login prompt?

[MillionMap]

I have an Instant App and a Web Map that I've been sharing with clients for months now.  For some reason they both now require login.  Everything is shared 'public', all layers and the App and Map are 'public'.

The only thing I've done recently was add an imagery layer from Living Atlas.  Was getting the login prompt when opening the Apps and then removed the layer.  Still getting the login prompts. 

[SWrdno]

EDIT* I am getting the same issue. This doesn't seem to be a problem when I publish through a Web Mapping Application, but it is in Experience Builder and Instant Apps. In EB the log in pop up can be canceled and you can still see all the data, but this still confuses my public users so must be fixed. 

I know this wasn't a problem 2 weeks ago when I was last viewing the map. 
My public EB: RDNO Evacuation Status Map (arcgis.com) 

[jcarlson · Accepted solution]

Check your basemaps. The most common cause for this is that your org is using developer basemaps, which aren't public. That or your basemap isn't shared publicly, but you don't always see that unless you go into the basemap settings and check each source one by one. If you edit the basemap to refer to a public source, the login prompt should go away.

Can you share the URL?

[MillionMap]

Thanks for the review.  This link with all its layers was working fine (publicly) until this week.

https://respec.maps.arcgis.com/apps/instant/basic/index.html?appid=5286304c5a0b41878581da2dfac0dfd4

[jcarlson]

Interesting. I can see everything just fine, whether I'm logged in or not. I see the linked web map, and nothing on there appears to be shared incorrectly. What was the imagery layer, if you remember? Did it come with any reference layers or hillshades that might still be in the basemap?

[SWrdno]

My map has no sign in required when viewing it through the Web App but only through the Experience Builder and Instant Map. My base map has not changed, it is the ESRI World Topographic Map. I never edited my map at all in the last two weeks and suddenly this sign in pop up appeared. 

Both of the below maps are referencing the same Web Map:

Public Web App (no sign in pop-up): https://rdnogis.maps.arcgis.com/apps/webappviewer/index.html?id=7bad055a64d54582abd3edd6b808d484

Public Experience Builder (sign in pop-up): https://experience.arcgis.com/experience/be253099f825488780b106ba04aa8f99

Any ideas?

[MillionMap]

It was an Amtrak Rail feature layer that was my problem.  It's status as a public layer had changed.  Removed it and replaced it with another.  Problem solved.

[ChrisWhitmore · Accepted solution]

Good to hear you sorted out the problematic layer even if it took some sleuthing to track it down. I just wanted to note there is an easy way to check if any sharing issues for layers in a web map. On the item page as the map owner (or administrator), you'll see a notice if a map has any layers that aren't shared at the same level as the map. It will show under the share section on the right hand side of the map's item page if any access issues are detected.

The review layer sharing link will open a dialog that lists any layers with access issues (along with the ability to update sharing if allowed):

It is only able to detect sharing issues for hosted layers and other layer items. It doesn't detect service issues that lead to access issues (like enterprise services that aren't accessible to the public or other service-level issues, etc) but should work well for catching any basic sharing issues especially when you have a map with lots of layers and need to track down a layer that has been unshared out from under the map.

Cheers,

Chris