# Err\_cert\_authority\_invalid

**URL:** <https://community.letsencrypt.org/t/err-cert-authority-invalid/218169>\
**Category:** Help\
**Created:** [May 10, 2024, 4:30pm UTC](https://community.letsencrypt.org/t/err-cert-authority-invalid/218169 "2024-05-10T16:30:03Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![Osiris](https://avatars.discourse-cdn.com/v4/letter/o/839c29/32.png) [@Osiris](https://community.letsencrypt.org/u/Osiris)\
**Post date:** [May 11, 2024, 10:51am UTC](https://community.letsencrypt.org/t/err-cert-authority-invalid/218169/5 "2024-05-11T10:51:12Z")

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Please see [Shortening the Let's Encrypt Chain of Trust](https://community.letsencrypt.org/t/shortening-the-lets-encrypt-chain-of-trust/201580)

Android 5 is missing the ISRG Root X1 certificate.

Also, Android 5 is probably extremely vulnerable due to missing security updates.

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_[View the full topic](https://community.letsencrypt.org/t/err-cert-authority-invalid/218169)._