Does not create appointments in backoffice

Hi,

This plugin stopped working at some point in time. We have got aware of this problem now.

The only change we had was:
1. Add custom fields
2. Update to the latest version.

It does not create appointments in backoffice and does not send emails to the admin account (or at least we did not received any).

Although, the visitor does receive the new appointment email.

Please, any help or idea about how to debug this problem is appreciated!

Thank you,
Marco