Problem
With one of your KM MFPs, you get an error "data from your card is invalid" when a swipe is done. You have also tried replacing the card reader, but it did not help/resolve the issue with the MFP.
In the Pharos logs for when a swipe occurred, there are no entries relating to when the swipe was attempted. Jobs from MyPrintCenter are still working, just not the swipes.
Solution
When this problem occurs and the logs do not have any entries, this is because the device is not sending any card values to the server which is the cause of the error.
In this case, please ask the KM Technician to validate that the reader is configured along with the device having the correct KM Loadable Driver for the USB Device installed.
The KM technicians should have a way to test the output from a card with the reader and they also need to install specific USB Drivers on the device(s) for the reader to operate correctly.