Spambots commonly target public forms in this way, not just those created with Gravity Forms. The first steps to combating it is to ensure the honeypot and submission speed check features are enabled in the spam detection section of the Form Settings page of the form.
On the Entries list page, using the column selector, you can enable display of the submission speeds, so you can use the values found in that column to refine the threshold in the form settings.
You can find additional spam detection/protection solutions on the following page of the documentation:
Our webops team are currently working on resolving the login fatal error that is occurring in the SSO process.