i18n: Instructions monero.social prohibits registration

Author: PyXMR2025

_i18n/en/resources/user-guides/join-monero-matrix.md

@@ -10,6 +10,8 @@ Go to [element.io](https://element.io/get-started#download) to download the late
 
 ### Setting the custom host server
 
+> Note: Registration for the `monero.social` host server is temporarily disabled.
+
 While matrix is a federated protocol and you could use any host server for your account (including the default matrix.org server). We recommend changing your server to the one hosted, maintained and [sponsored]({{ site.baseurl }}/community/sponsorships/) by the Monero Community to support decentralization. If you do choose this option remember to set your custom server when logging in on a new device.
 
 When signing up choose to edit your host server and type in `monero.social` as shown.