You can browse the following URL to troubleshoot the Card related issues:
https://127.0.0.1:8440/api/v1/card/getmessage?nowaitTo
The response is displayed in the following format:
{ result: [<status>], cardid: <card id>, readerid: <reader id> }
The following are the different status that are displayed as response for the Card service:
NO_READER: Indicates that the card service is unable to detect the connected card reader.
READER_ON: Indicates that the card service detected the connected card reader.
NO_CARD: Indicates that there is no card on the reader.
CARD_ON: Indicates that a card is presented to the reader.
NOTE:The cardid parameter is used only with the CARD_ON and NO_CARD statuses.