If your organization hosts The Raiser's Edge
Confirm Raiser's Edge is on 7.96 Patch 8+. If Raiser's Edge is not on Patch 8 or above, users will see a runtime error when accessing the email preferences part, due to the new Communications Consent Options implemented between Raiser's Edge and NetCommunity. Download and install the latest patch from downloads.blackbaud.com.

After The Raiser's Edge has been updated to 7.96 Patch 8+, make sure to log into your REWS (NetCommunity) server. Open the The Raiser's Edge client on that machine to initiate the update on the REWS. 

Verify the The Raiser's Edge is on 7.96 Patch 8+. How to check for the current version of Raiser's Edge
NOTE: If the The Raiser's Edge client on the REWS does not update after opening the application, it may not be able to access the deploy kit over your network. Your  IT team will need to troubleshoot the connection or you can move a copy of the updated deploy kit to the REWS server to perform a manual update. For more information about the deploy kit, see: What is the Deploy Folder and what is it used for?  and How to manually update The Raisers Edge application on the Blackbaud NetCommunity web server

Once you have verified that The Raiser's Edge has been updated to 796 Patch 8+ for both the main application and the client installed on the REWS, if you are still getting the error follow these steps for How to Recycle Application Pools for Blackbaud Products

Other scenarios
Typically, clicking the link again will allow the user email preferences page to display. If the error persists, direct users to the User Email Preferences page on your website. For users with a username, they can log in and change their preferences on this page. For users who do not have a login, they must make the change through another email.