@LE-19051254-0
Good detective work — and this clears things up nicely. Since your colleagues can already open the SharePoint lists directly in the browser, the SharePoint side is fine. The only thing still wrong is how the app itself was shared. Let me answer your questions one by one.
Is your team a security group or a Microsoft 365 group?
The fact that your team has a team email is the dead giveaway — it's a Microsoft 365 group. Every team you create in Microsoft Teams automatically has a Microsoft 365 group behind it, and that group is what you share the app with. You don't need to create a separate security group.
If you ever want to confirm, an admin can check at admin.microsoft.com under Teams & groups → Active teams & groups — your team will be listed there with the type "Microsoft 365".
Sharing in a Teams chat is not the same as sharing the app:
This is the missing piece. Pasting an app link into a Teams chat does not grant anyone access — it just sends them a link they can't open without permission. To actually share the app:
• Go to make.powerapps.com
• Find your app, click the three dots, then Share
• In the search box, type the name of your Team (the same name as in Microsoft Teams)
• It will show up as a Microsoft 365 group with the Teams icon
• Select it and click Share
Now everyone in that team will be able to open the app without requesting access.
Optional but cleaner — Add the app as a Teams tab:
After sharing, on the same Share page in make.powerapps.com there's an option to add the app to Teams as a tab in a channel. That way your team finds it inside Teams itself, without needing the link at all. This usually feels more natural for end users than a chat link.
Once you've shared it with the Microsoft 365 group, ask one of your colleagues to refresh and try opening it again — it should work straight away
