Some China users cannot login or find the teams chat using mobile / some history messages were missing before 31Mar2026

Question

I have set up a teams CHAT. More and more users (especially those from Mainland China) faced problems when logging in their microsoft teams account and cannot locate my CHAT group.

Also, i just found that the message history before 31Mar2026 cannot be located using 'search' function, those after were all here.

Any clues or recommendations of solutions?

Thanks a lot!

Answer 1

Hi @Peter,

I hope you’re having a great day. Thank you for raising this and sharing the details really appreciate it. 

I understand the impact when users (especially from Mainland China) can’t sign in reliably or can’t find the chat group, and when older messages don’t appear in search. 

Below are the most likely causes and the recommended next steps: 

1/ Mainland China users can’t log in / can’t find the chat group (mobile) 

• If your tenant is Worldwide/Commercial, users in Mainland China can experience unstable connectivity due to cross‑border congestion (high latency/packet loss), which can affect Teams sign-in and chat list synchronization.  
• And if any affected users are on Microsoft 365 operated by 21Vianet (China cloud), that environment is physically separated from the Worldwide cloud, and cross‑cloud chat has known limitations. 

Therefore, please confirm whether the affected users are signing in with accounts in the same Worldwide tenant as you, or if they are using a 21Vianet (China) tenant. 

• For Worldwide tenant users in Mainland China, Microsoft recommends network optimization (e.g., corporate private link/VPN with egress outside China such as HK/SG/JP/KR) to reduce cross‑border impact. 
• If users are on 21Vianet and need to collaborate with your Worldwide tenant, you may consider a cross‑cloud collaboration approach (e.g., cross‑cloud guest access / cross‑tenant settings) rather than relying on a standard group chat alone. 

More info here:  

• Microsoft 365 global tenant performance optimization for China users - Microsoft 365 Enterprise | M… 
• Microsoft Teams chat experience when communicating with people outside the organization - Microsoft… 

2/ Messages before 31 Mar 2026 not returned by “Search” 
Two common explanations could account for this behavior: 

• A retention policy may be deleting/limiting older Teams messages based on the message creation date. 
• The messages may still exist in the backend, but Teams search may not return them due to indexing/visibility issues. Teams 1:1 and group chats are stored in Exchange Online mailboxes.

Given this situation, I suggest contact your organization’s IT administrator to verify whether any Microsoft Purview retention policy is applied to Teams chat/channel messages, and whether it could explain the cutoff around 31 Mar 2026.  

Also, please ask them to confirm whether the older messages still exist by running a Microsoft Purview Content Search / eDiscovery. 

Additional guidance: Manage retention policies for Microsoft Teams - Microsoft Teams | Microsoft Learn 

Should your IT department cannot access the necessary information or make the required changes, I recommend asking them to open a request with Microsoft Support team through the Microsoft Admin Center. They have access to backend configurations and can perform a more in-depth investigation. At the very least, they can provide the most effective workaround to ensure your experience remains smooth and secure.     

In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support  

As community moderators, we appreciate your understanding that we do not have access to the administrative tools or permissions required to investigate or modify these configurations. We also do not have the capability to initiate remote sessions for direct assistance. Our role is to guide users to the appropriate resources and support channels.  

I hope this information is helpful. Should you have any further questions or need additional assistance, feel free to reach out.   

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Answer 2

For China-based users who cannot log in to Teams mobile or find a specific chat, and for missing/“unsearchable” older messages, there are two likely, separate issues:

1. China users: Teams mobile not working / can’t find chat
   On some Android devices, recent vendor updates have broken Microsoft apps (including Teams and Outlook). For example, a Samsung April 2026 security update caused a WebView regression that stopped Microsoft apps from working. The documented fix is:
   1. On the affected Android device, go to Settings and search for “Android System WebView”.
   2. Select App details in store.
   3. Choose Remove updates for Android System WebView.
   4. Reboot the device.
   5. Go back to Settings → Android System WebView → App details in store and Update it again.
   6. Reboot once more, then launch Teams and sign in.
   If Android System WebView does not appear in the app list:
   1. Go to Settings → Google → All services → System services.
   2. Select Android System WebView.
   3. Reboot, then launch Teams and sign in.
   This resolves cases where Teams opens but cannot load content or connect properly, which can appear as login issues or missing chats on mobile while everything works on PC.
2. Chat history before 31 Mar 2026 not appearing in search
   The provided context does not describe a specific cause tied to that exact date, but there are a few supported behaviors to consider:
   • Hidden or removed chats – Users can hide chats or remove chat history from their own view. When a user selects More options → Remove chat history on a one‑on‑one chat, the chat is removed from that user’s list and can no longer be accessed, including through search, although the other participant still sees it. If some participants removed or hid the chat, they will not be able to find older messages via search.
   • Per-user behavior – Removing chat history is per-user only; it does not delete messages for everyone. So some users may still see older messages while others cannot.
   To check whether this is the issue for specific users:
   1. Ask them to open Chat and look for the conversation in the list.
   2. If it is not visible, have them try to search for the other participant(s) by name to resurface a hidden chat. Hidden chats can be recovered by searching for them.
   3. If they previously used Remove chat history, those messages are no longer accessible or searchable for that user.
3. General troubleshooting when chat content doesn’t load or appears incomplete For users whose chat list or messages are not loading correctly (especially on mobile):
   1. Restart Teams to force a refresh.
      • On desktop: quit Teams from the taskbar (Windows) or use Force Quit on macOS, then reopen.
   2. Check internet connectivity by opening a browser and visiting any website.
   3. If using the desktop or mobile app, try the web version at https://teams.microsoft.com/ to confirm whether the issue is device/app-specific.
   4. Sign out and sign back in to Teams: select the profile picture → Sign out, then reopen Teams and sign in again.
4. China-specific network considerations (for completeness) For China users, network conditions can affect Teams behavior. Microsoft recommends:
   • Connecting via a stable local internet connection in China (landline or mobile). Teams real-time media (audio/video) benefits directly from improved connectivity.
   • If using VPN/SD-WAN, consider split tunneling so that Teams real-time media traffic (ID 11 in the Microsoft 365 URLs and IP address ranges) goes directly to the internet, while other Microsoft 365 traffic can still use VPN/SD-WAN. This mainly affects call/meeting quality but can also reduce general connectivity issues.

If, after applying the Android WebView fix and the general Teams troubleshooting steps, China users still cannot log in or find the chat, collect details (device type, OS version, whether web Teams works, and whether only older messages are missing) and escalate through Microsoft Teams support.

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References:

• Microsoft 365 global tenant performance optimization for China users
• My chat messages aren't loading in Microsoft Teams
• Hide a chat, remove chat history or leave a chat thread in Microsoft Teams
• My Microsoft Apps have stopped working on my Samsung Ultra S25 - Microsoft Q&A