Login fails

I’m testing this plugin on 2 dev sites that are linked in one direction. Currently I have only this plugin active along with the 2024 official theme.

I’m getting the error 2024-01-15 14:40:00 - Alert - Login action failed - received invalid data When I try logging in on the source site. The data in the log is:

Array
(
    [data] => Array
        (
            [username] => test
            [remember] => 0
            [base_url] => https://subdomain.wpengine.com
        )

)

The outgoing site log reports no error in the log:

2024-01-15 14:39:59 - Info - Added https://learntmirldev.wpenginepowered.com/wprus/login/?wprusdata=Cdg_ ... 5c5 async URL in admin_footer

I’d be grateful for any help in debugging this. I know the plugin works but I’ve set it up correctly and now I don’t know what is invalid about the received data.

All the tests on the Remote Sites tab succeed.

Cheers.