Subscribe by Email not working on a Domain Mapped Subsite

I am in the process process of moving a client’s site to my multisite as a mapped domain.

I’ve been double checking each all the settings to make sure they match to the originals single site as much as possible.

I’m almost done –

The Domain Map is working

The Contact Form 7 is working.

Where I m running into a problem is Subscribe by Email.

Should the Plugin be Network Activated – or just on the Mapped Domain?

I tried both – so I’m not sure what’s wrong.

On the previous hosts single site –

under Subscriptions > Settings > General Settings – I had the field “Notification from Sender” set to

If I only have the Plugin Activated on the Mapped Domain there is nowhere to fill in the “Notification from Sender” field – and if I send a test message I get the white-screen of death.

If I have the Plugin Network Activated – the field setting appears under Network Settings and there doesn’t seem to be a way to set a different email for the Mapped domain.

Is this Plugin not multisite capable?

Please advise what I should do.