Portal web application basemap gallery has a 'ghost' item

[KipoKipo]

I am working on our organization's Basemap Gallery, which basically are a bunch of web maps of imagery that are shared to the Basemap group. These imagery are set as basemap in the web maps. When I use Basemap widget to add the group, there is always a 'ghost' item showing in the gallery. This ghost item (World Topo Map) is not added in our basemap group and it doesn't have proper icon with it. See the attached picture.

Thanks all

KP

[JonathanQuinn]

If you were to click on the basemap widget with Fiddler or the dev tools running, do you see a 404 error when it tries to get the image for that particular basemap?  Is this an upgraded Portal, and was it working previously?

[KipoKipo]

Thanks Jonathan for your reply! Yes this is new when migrating to 10.5 server. I used Fiddler to watch the traffic, and only found it making request to server.arcgisonline.com:443 successfully. The issue is that I don't have World TOPO map in my basemap group. It confuses me. 

KP

[JonathanQuinn]

Did you run a full re-index, steps 10-12 in the link below?

Upgrade Portal for ArcGIS—Portal for ArcGIS (10.5.x) | ArcGIS Enterprise 

[KipoKipo]

Nope I didn't. Sorry I didn't mention that this is a new installation and not a upgrading from the old system. Do I still need to do re-indexing in this case? 

Thanks!

[JonathanQuinn]

No, that's only for upgrades.  Did you set Fiddler to decrypt HTTPS traffic?

You can also use the dev tools within your browser which decrypt HTTPS traffic by default.

It'll be important to see the responde code from the request for the thumbnail, (404, etc).

[KipoKipo]

I used IE dev tool and couldn't find missing thumbnail. 

Since I couldn't get rid of this item, I choose to add the World Topo service in the basemap gallery widget and assigned the proper thumbnail to it.  Seems by doing this, the new item replaces the old weird one as expected.

At least it looks fine now.

Thanks!

[LaurensGIS]

In case others experience this problem, here is what I encountered.

I created a webmap and added a service as a basemap. In the webmap I renamed the folder with the basemap to i.e. "basemap 1". I shared this webmap with the Basemap group.

I created another webmap (webmap 2), added some operational layers, choose the "basemap 1" as my basemap. I created a webapp and used this webmap in the webapp. In the webapp I only saw "basemap 1" in the Basemap Gallery.

Now I went back to the first webmap, renamed the folder with the basemap to "basemap 2". 

I refreshed my webapp. Now there are two basemaps I can choose from: basemap 1 and basemap 2. 

In my opinion this should not be possible, since there is only one webmap shared in the Basemap group.

I solved the problem by going back to webmap 2, click on the basemap gallery button and select "basemap 2".

Refreshed the webapp. And now there is only one basemap to choose from: basemap 2.