The PivKeyTool executable uses the first smart card reader it finds. If you have multiple readers (or tokens), and the first reader it finds is not a PIVKey (or is empty), PIVKeyTool will show a "cannot connect to the reader! " error.
We recommend that you use only a single reader or token at a time. The order of readers is determined by the Windows PCSC interface. This order can change and is not reliable.
However, if you must have multiple readers you can use the --reader PIVKeyTool option to direct it to a specific reader. For example:
pivkeytool.exe --listmd --reader "Identiv SCR3500 A Contact Reader 0"
You can get the name of the readers attached to your system by running: