diff --git a/vector/src/withpinning/res/raw/tchap_preprod_letsencrypt.der b/vector/src/withpinning/res/raw/tchap_preprod_letsencrypt.der
new file mode 100644
index 0000000000..b7377ec9c8
Binary files /dev/null and b/vector/src/withpinning/res/raw/tchap_preprod_letsencrypt.der differ
diff --git a/vector/src/withpinning/res/xml/network_security_config.xml b/vector/src/withpinning/res/xml/network_security_config.xml
index 28e72a1ff2..bfb8da0e42 100644
--- a/vector/src/withpinning/res/xml/network_security_config.xml
+++ b/vector/src/withpinning/res/xml/network_security_config.xml
@@ -6,6 +6,7 @@
             <!-- Do not allow system and user certificates by default -->
 
             <!-- Allow only Tchap intermediate certificate authority -->
+            <certificates src="@raw/tchap_preprod_letsencrypt" />
             <certificates src="@raw/harica_tls_root_2021_rsa" />
             <certificates src="@raw/servicesca_rootca" />
             <certificates src="@raw/certignaserviceseurootca" />