Typical mistakes with zone expander connection is not hooking up the COM (common) wire for zones on the expander. The user manual:
https://openthings.freshdesk.com/support/solutions/articles/5000716364-opensprinkler-user-manuals
page 4 at the top shows a diagram of the correct connection.
Look, if you are looking for support with your existing system, you should submit a support ticket — the forum is not the right place to ask for support, especially if you need urgent help — we don’t check forum posts on a regular basis; to start the support process, we need you to provide your order number, so we can check exactly what you have ordered; we also frequently ask you to attach a copy of your configurations, which I am sure you don’t want to put them on a public forum.