# Invalid server certificate on android app

**URL:** <https://forum.mattermost.com/t/invalid-server-certificate-on-android-app/20631>\
**Category:** Mobile Apps\
**Created:** [October 17, 2024, 5:34am UTC](https://forum.mattermost.com/t/invalid-server-certificate-on-android-app/20631 "2024-10-17T05:34:39Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Valwereth](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mattermost.com/valwereth/32/8333_2.png) [@Valwereth](https://forum.mattermost.com/u/Valwereth)\
**Post date:** [October 17, 2024, 5:34am UTC](https://forum.mattermost.com/t/invalid-server-certificate-on-android-app/20631/1 "2024-10-17T05:34:39Z")

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our company just recently started to use mattermost. We have received an invitation to the server, registered, connected. Desktop app works, in browser also works, but whenever i try to connect by android app, it shows me “The certifcate for this server is invalid. You might be connecting to a server that is pretending…”  
My teammates were able to connect by app, on IoS and Android.

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**Author:** ![john.oliver](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mattermost.com/john.oliver/32/6436_2.png) [@john.oliver](https://forum.mattermost.com/u/john.oliver)\
**Post date:** [October 17, 2024, 2:20pm UTC](https://forum.mattermost.com/t/invalid-server-certificate-on-android-app/20631/2 "2024-10-17T14:20:26Z")

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I think you need to ensure that the AndroidOS trust chain trusts not only the certificate of the Mattermost server, but any and all intermediate CAs and the root CA.