Flow can't find production SharePoint URL (on-premises) but Gateway works fine and connects to demo site

[gbdavid2]

We have 2 separate SharePoint Servers (one demo and one production). I have installed an on-premises data gateway in a PC that can access both servers fine. I can use the exact same domain user to connect to both sites. I'm not an administrator, but I have authoring rights in the sites of both servers.

When I try to log in to create the trigger step for the demo / test server, everything works fine:

However, If I try to create the same step connecting to the production server, Flow can't find the URL:

Could there be something disabled in the production server that is enabled in the demo server that is blocking this?

Other notes to consider:

• I have checked the URLs (demo + production) and I can access them correctly from the Gateway location. These are on-premises servers that cannot be accessed from outside the network but can be accessed via the Gateway.
• I have checked in make.powerapps.com and the data gateway is online and it is also in the correct environment
• I have checked in flow.microsoft.com and I can also see the gateway fine
• I created a connection to the gateway in the trigger action that uses windows authentication which is the same authentication I use in the pc that has the gateway installed.
• The trigger action works fine for the demo server and when I execute the flow it works correctly. The trigger action can't find the URL for the production site so I can't test the flow using that URL at all.
• As I'm using a 'When a file is created or modified in a folder action', the URL I'm giving is the root of my document library (e.g. https://mysite.com/sites/subsitedemo/Documents
• The document library that I'm trying to access in the production site is in a slightly different location but I'm still giving the root of the document library to the trigger action. If I try a 'For selected Item' trigger where the URL is the root of SharePoint (e.g. https//mysite.com) I have similar issues (demo works fine but production doesn't).
• I don't have administrator rights to access the Administration Center of the servers, but I can contact my administrator with a request to check things, but I don't know what to ask them as I have similar rights in both servers. 

Update 1:

I have worked with our SharePoint Administrator and we have done the following tests:

- Created a new Gateway using his Administrator account login credentials. This gateway was visible to me in the make.powerapps.com site under the correct environment and region. This gateway was also visible to my administrator within his Flow portal (unitedkingdom.flow.microsoft.com).

- My SharePoint Administrator created a similar flow as above within unitedkingdom.flow.microsoft.com and he created a connection using his administrator account and his new gateway.

- The similar problem happened: 1. Demo site connects successfully and can show all the lists/objects in the Folder Id filed and recognises the URL of the demo site. 2. For the Production site it can't find the URL at all.

- Note: My SharePoint Administrator has full access rights to both production and demo servers. He also has full access to the Central Administrator portal of both SharePoint servers. 

We have ruled out any connectivity issues between the PC where the Gateway resides, and the Flow Servers - The connection tests from the Gateway App are successful, and make.powerapps.com can see the Gateway and shows the status as Online. If we try to open a web browser and browse to both SharePoint subsites they are accessible with the administrator accounts as well in the

Gateway PC so we really don't know what's going on.

Update 2:

As an additional test I (as a .NET developer), tried a quick console application using SharePoint CSMO (https://docs.microsoft.com/en-us/sharepoint/dev/sp-add-ins/sharepoint-net-server-csom-jsom-and-rest-...).

When I tested it, the demo server successfully retrieved the lists from the subsite, however when testing the Production server, it just showed:

System.Net.WebException: 'The remote server returned an error: (401) Unauthorized.'

Furthermore, the reference documentation advises that the API tries to access the website in this form:

http://<site collection>/<site>/_api/web/lists

so this is what happened when I tried to access the demo site api (from a web browser):

and this is what happened when I tried to access the similar subsite api in the production server (from a web browser):

I'm not sure if this has anything to do with Microsoft Flow (Power Apps), but I suppose if Flow uses a similar technique to access the site then this might be part of the problem? (Note that Flow is not saying anything about access denied, it just says that it can't find the URL as seen above in the first screenshots).

Update 3:

I've also noticed a clear difference between our test server and our production server. Our test server uses standard Windows Authentication to log in, however our Production Server uses ADFS, however, we can log in to both servers using the same user@domain and password - Not sure if this is a problem for Microsoft Flow? - It still doesn't explain why Flow is saying that the URL doesn't exist, it should be showing a different error?

Any ideas?

[psycrkz1]

Have you fixed this issue in the end?

[Anonymous]

Any update on this? This is killing my soul. Please fix this nonsense.

[gbdavid2]

We were never able to fix it 😞 - I mean, possibly something needs to be done by the Power Apps developers to fix this issue in the code / network authentication modes etc, if no one has been able to contribute a solution to the problem in over a year 😑

[Theresa]

I just had this problem and did 2 things, but I'm not sure which one fixed it. 

1. I added the SharePoint trigger "When an item is created or modified." Rather than using an existing connection, I created a new one. 
2. Even though I typed the entire URL (https://mysite.constoso.com/sites/site1), after a very quick system-initiated refresh (more like a blip), only the first part of the URL still appeared (https://mysite.com). So I added the next part of the URL, which was just the root site (https://mysite.contoso.com). I was then able to click the dropdown and see all of the lists for the root site. Then I added the rest of the URL, resulting in the full site collection URL (https://mysite.contoso.com/sites/site1). I clicked the dropdown again and now had all of the lists for the site collection. 

[Ashikgupta]

I am also facing such type of issue, in one step of the flow I am creating a file at Sharepoint with my user id connection which is working fine. But when I tried same step with other common user id with same access level on Sharepoint I am not getting site address in drop down. When I tried to forcefully enter the site information using custom then flow get failed in execution by giving authorization error at this step.

Please comment if anyone will get any solution for such type of scenario.