Problem

When contacts try to confirm receipt of an Email or SMS message, they receive the following message:

We appreciate your response, but you already responded to this message

Root Cause

This message occurs when the link has already been confirmed by the email or SMS notification service prior to the recipient confirming the message.

1. For email notifications, filtering services validate links and URLs in emails to keep malicious content out of inboxes; this validation process can result in the service "clicking" the confirmation link to ensure Everbridge is not sending anything harmful. An example of such filtering services is the Safe Links feature in Microsoft Office 365. When this feature is used, the message will be automatically confirmed once the contact clicks to view the email.

2. For SMS notifications, some smart phones have a web link preview feature turned on by default. If this feature is enabled, and the Include Short URL in SMS Confirmation feature/flag is enabled in Everbridge, SMS messages are previewed and confirmed automatically. For more information on the Include Short URL in SMS Confirmation feature/flag, see knowledge article EBS: Enabling the Short URL in SMS Messages for Organizations in Everbridge Suite.

Solution

Disable the automatic confirmation behavior of email and/or SMS notifications.

1. For email notifications, add https://neconfirm.everbridge.net to the email filtering service's managed (or permit-listed) URLs. For more information on email permit listing, see knowledge article EBS: Everbridge Permit Listing Best Practices. 
2. For SMS notifications, disable any Show web previews features in the messaging app settings. Disabling such features stops auto confirmation. For Android devices, please navigate to your Messages app and open settings. Click on More Settings and Enable/Disable Show web previews.  Please note that this setting cannot be disabled on iOS devices.

Note that not all devices experience the same behavior. It is for this reason that Everbridge recommends the use of multiple delivery methods so that the individual is targeted and not the device.