You might encounter issues with displaying mashups after an upgrade because of the latest security enhancements.
When the system receives a mashup request with the isWebMashup=true parameter and a blank channelID parameter, the system displays an error page with the following message: This mashup is not consistent with the latest security enhancements. Regenerate the mashup to include the channel ID in the snippet.
After an upgrade to Pega Platform 8.5, the system cannot load the existing mashups, which do not have the channel ID parameter in their code, and displays the access control warning.
Create a new mashup in your upgraded version of Pega Platform, and ensure that the data rule is included in your upgrade pipeline. As part of this process, generate the new mashup code, and redeploy it to the appropriate external websites to ensure that your mashups function as intended.
For additional information, see Creating a mashup.