Bug Report: Unable to Add App via Developer Portal or Upload PKG

[showtarow18]

We used to be able to add our app via the "Preview in Teams" button in the Developer Portal. However, recently when we click the button, the app addition modal appears for just a brief moment and then disappears, and the app is not added to Teams.

Additionally, we tried uploading the app package (.pkg) manually via "Upload an app" in the Teams UI, but the option is now disabled and cannot be used. This used to work without issue in the past, but now it seems to have stopped functioning.

Has there been a change in behavior due to a recent release or update?
Please let us know what we need to do to successfully add our app again. If this is a bug, we would appreciate it if you could fix it.

2025-06-23.19.39.50.mov

[m365-agent-toolkit-assistant]

👋 Hi @showtarow18,

Thank you for reporting this issue! We want to let you know that:

⏱️ Our team will personally review your issue
🎯 You can expect a response within 2 business days

✨ This is an AI-generated initial response
🤖 AI-Generated Preliminary Analysis:

There are several known issues matching your symptoms (‘Preview in Teams’ modal disappearing, “Upload an app” greyed out). Here are actionable steps and references:

1. Check for Policy Changes:

   • In the Teams Admin Center, verify under “Teams apps > Manage apps” that “Allow uploading custom apps” is enabled for your org.
   • Go to “Teams apps > Permission policies” and ensure your user has permission to upload custom apps.
   • Setting changes can take up to 24 hours to propagate (reference).

2. Manifest / App Package Issues:

   • Ensure your .zip/.pkg does not contain any zero-byte files (especially icons). This has caused upload failures previously.
   • Double-check that your manifest adheres to Teams schema requirements (example issue).

3. Platform Changes:

   • Microsoft does occasionally update policy defaults for custom app uploads — confirm with your Teams admin if there were recent policy changes.

If all settings are correct and the issue persists:

• Clear Teams’ cache and try a different browser/device.
• Report the error with details at GitHub, referencing the similar issues above.

Let me know if you need help checking policies or have your manifest reviewed!

✨We'd love your feedback! Please take a moment to fill out our survey.

---

Note: This is an automated first response generated by AI. A human team member will review your issue and provide a more detailed response soon. We appreciate your patience!

[showtarow18]

📝 Suggested Issue Reply (Policy Confirmation)
Thank you for the preliminary response.

We have reviewed our policy settings as suggested, and can confirm the following:

"Upload custom apps" is turned On in the Global (Org-wide default) app setup policy.

The target app is marked as "Available to everyone", meaning it should be installable by anyone in the organization.

The permission policies and setup policies have not restricted custom app uploads.

Please find attached the following screenshots for reference:

App setup policy configuration showing "Upload custom apps: On"

App availability settings confirming it is available to everyone

Despite these correct settings, the issue still persists:

The "Preview in Teams" modal still disappears immediately.

The "Upload an app" option remains disabled in the Teams client.

Could you please advise on any recent changes or additional settings that might be affecting this behavior?

[showtarow18]

📝 Additional Issue Report: Upload Button Behavior Depends on Language Setting
We’ve discovered additional unexpected behavior that may be related to localization or caching inconsistencies in the Teams desktop app.

🔍 Summary of the Issue:
When the Teams desktop app is set to Japanese, the “Upload an app” button is enabled in the “Manage your apps” view.

When we switch the language to English (United States), the same button becomes disabled.

Switching back to Japanese re-enables the button again.

🗂️ Related Behavior:
In Japanese, we also see a “Pending requests” section that no longer appears in English.

We had previously deleted all pending requests via the web portal, yet the Japanese UI continues to show them.

Restarting the Teams app does not synchronize this change — it appears to be cached or otherwise out of sync.

We’ve attached screenshots showing the difference between the two language settings for reference.

❓ Questions:
Is this a known issue?

Is there a way to force a refresh or fully clear Teams’ internal cache beyond just restarting?

We appreciate any insight into whether this is expected behavior or something that needs to be addressed.

[HuihuiWu-Microsoft]

This is an issue from upstream service. I've reported to related team and they're investigating this.

[PauwelsYoran]

Hi, I'm experiencing the same issue. Has any progress or workaround been found?

[HuihuiWu-Microsoft]

@PauwelsYoran The fix has been merged but it will roll out to R3 on 07/10, R4 on 07/21 as mentioned by service team.