Troubleshooting

Before you can install the Plain app in Microsoft Teams, your Teams tenant administrator may need to enable custom app uploads. Follow the steps below to configure this in the Teams Admin Center.

1. Allow custom apps org-wide

1. Go to Teams apps → Manage apps

2. Click the Actions dropdown then Org-wide app settings

3. Ensure "Let users interact with custom apps" is toggled On

4. Ensure "Let users install and use available apps" is toggled On

5. Ensure "Third-party apps" is toggled On

6. Click Save

2. Enable "Upload custom apps" in the setup policy

1. Go to Teams apps → Setup policies

2. Click on Global (Org-wide default) (or create a new policy if you only want to allow specific users — see note below)

3. Toggle "Upload custom apps" to On

4. Click Save

5. If using a custom policy, assign it to the relevant users via Manage users

3. Check app permission policies

1. Go to Teams apps → Permission policies

2. Select the relevant policy (e.g. Global)

3. Under Third-party apps and Custom apps, ensure apps are set to Allow all apps (or that the Plain app is explicitly allowed)

4. Click Save

Restricting uploads to specific users only

If you don't want all users in your organisation to be able to upload custom apps, you can scope it to specific people instead of editing the Global policy:

1. Go to Teams apps → Setup policies

2. Click Add to create a new policy

3. Give it a name and description (e.g. "Custom app uploaders")

4. Toggle "Upload custom apps" to On

5. Click Save

6. Select the new policy, click Manage users, and add the specific users who should be allowed to upload

7. Leave the Global (Org-wide default) policy with "Upload custom apps" toggled Off

Only users assigned to this custom policy will be able to upload apps.

Important notes

• Changes can take up to 24 hours to take effect.

• After setup, users can upload the app via Apps → Manage your apps → Upload an app → Upload a custom app.

Reference

• Manage custom app policies and settings

• App setup policies