Homeserver: https://matrix.obr.sh
This address is for a Matrix app, not for a browser. In Element X, change the account provider to matrix.obr.sh and sign in with your account. The admin creates the accounts: registration is closed and the server does not federate.
Push: Element X gets notifications through ntfy (UnifiedPush). In the ntfy app, set the default server to https://matrix.obr.sh, then pick ntfy as the push provider in Element X.