Resource not found errors for SPO data sources for 1 user

[PowerFox]

I have a technical issue on one of my apps where data connections such as a SPO List or Document Library will not load for one user. The navigation menu is a gallery based on a SPO list, so the app pretty much shows a blank screen. This happens when the app is launched in Teams or a browser. Other apps load fine using the same way to generate a menu from a gallery.

Things I've already done:

- I've checked and verified (With the permission check tool) that the user has access to the data sources.

- I've checked and verified sign-ins in Azure AD that the user is not using some other account by accident.

- I started a Monitoring session and that's when I learned that not all data sources are not found by the user.

Response: 

"statusCode": 404,
"message": "Resource not found"

The Office365Users data source is loaded succesfully.

- I used a test account with the same permissions and everything loads fine. 
- I also have the consent popup set to bypass so the user is not bothered with this stuff. But if this was an issue it should break the app for everyone else too.

So...I'm unable to reproduce the problem right now and Power Apps does not have an 'impersonation' feature. 

I love to solve these kind of puzzles, but I feel like this is some sort of bug. Any ideas guys? 

Thanks!

[PowerFox]

After more testing it appears that this only happens with newly added sharepoint list data sources.

I created a new sharepoint list and connected it as a data source and it will not connect for that particular user.

I also added a sharepoint list as a data source that this account has access to in another app, also failed to connect.

Existing data sources that i haven't recently added are connected properly.

This is clearly some sort of bug...

[Anonymous]

I'm kinda having the same issues where for 1 user the data sources are not connecting. I even made this user Co-Owner so I could figure it out. The datasources (Sharepoint Online) are not connecting. When I browse the backend URL from the Sharepoint list it does seem to work find under his account....

[PowerFox · Accepted solution]

Alright. After no response from Power Apps support I went into the trenches myself and was able to solve it. It was a major BUG as I already expected. Here's how I was able to find out:

1. Added end user to the Power Apps Environment to check out the connections. Looked fine. Removed them, loaded the app, agreed to consent, app was still blank. 
2. I Exported and Imported the app as a New app, no results for the end user published version.
3. Added the end user as a co-owner of the app to check out what happens in Edit mode. In Edit mode the consent screen popped up and I agreed to all, everything loaded FINE in the copied app in Edit mode. After saving and publishing that as the end user everything worked fine as well. Cool.

4. Alright, so now I added the end user as co-owner in the actual app and went into Edit mode again and this is when I found out that the most recently added data sources were all defined as 'Office 365 Users' instead of 'SharePoint'. I am not kidding you guys. Power Apps was trying to connect to SharePoint with a 'Office 365 Users' connection for this particular user.

5 After a moment of crying I trashed these faulty data sources and re-added them again as a SharePoint data connection as the end-user and published the app (My own account showed all the data sources perfectly fine).

Everything works fine again now for everyone, but I hope this doesn't occur ever again.

TLDR; Power Apps messed up the data sources types and it tried to connect to SharePoint with the wrong data source type.

-- 

Edit: I looked over the Monitor log again and I now understand it better. In the Request URL it said "https://europe-002.azure-apim.net/apim/office365users/*****"  before instead of "https://europe-002.azure-apim.net/apim/sharepointonline/****" This should be helpful to identify the issue quickly if it every occurs again.