You may have received an email from Salesforce last month with ACTION REQUIRED in the subject line.
This email was sent to the Salesforce System Administrators of some orgs that have moved from the one instance to another on 19 August.
This change was to improve performance and to better position your org for growth.
We have observed that this change has affected some Organisations, particularly those who use Zapier.
We recommend that you check all your integrations and forms - including your donation forms - just be sure that everything is connecting as expected.
For more information about release and maintenance schedules for your new instance, review the Salesforce Release and Maintenance Schedule article.
It is important to note your Instance (in Setup --> Company information) so that you can easily search by this on the Salesforce Trust site.
Note: org is short for organization (with a z) - a deployment of Salesforce with a defined set of licensed users. An organization is the virtual space provided to an individual customer of Salesforce.
Organisations (with a s) means charities, non profits and businesses that use Salesforce.