Is this an app you developed on Qlik Sense Desktop and uploaded to Qlik Sense Server? If so, are you using visualization extensions? If so, you need to upload the extensions to the Qlik Sense Server from the Extensions section of the QMC.
Even though being a KPI or gauge, still it could be a Visualization Extension instead of the built-in gauge and kip object of Qlik Sense.
Please double check it, because the message "The visualization was not found on the server" appears when an Extension is used in an App but it wasn't imported to Qlik Sense. Import the extensions via the Extensions section of the QMC.