OK - I found this other support post:
https://support.gluu.org/single-sign-on/7649/unable-to-login-with-email/
In oxTrust go to “manage authentication” the “manage ldap authentication” tab and press activate.
Pressing ‘activate’ fixed the CASA login. It now logs in OK with email and password! Yay!
But I now can’t login to oxTrust :(
I’ve put a comment on that post with the details of my current error…
https://support.gluu.org/single-sign-on/7649/unable-to-login-with-email/#at70043