UPM fails to upgrade plugins with Unexpected token message on console
Platform Notice: Server and Data Center Only. This article only applies to Atlassian products on the server and data center platforms.
Sometimes UPM fails to upgrade plugins and a popup error message appears. It says it failed and to check the Confluence logs but the logs have no errors.
Open the browser’s console and try to upgrade a plugin. You will observe the following message:
Failed to parse response text: SyntaxError: Unexpected token U in JSON at position 0
JSON.parse() on a string beginning with u instead of a stringified object. "u" is typically a stringified version of the undefined primitive.
- Clear the browser's cache or use the incognito mode
- Try to upgrade the plugins again