No valid signature capture licence found

When running sign pro PDF or a signature application built for use with the Wacom Signature SDK this error can occur in the following situations:

• No signature pad is connected to the PC
• A signature pad is connected but Windows does not recognise it (this will probably show as an error in Device Manager)
• A signature pad is connected but it wasn't manufactured by Wacom
• You are using a touch-screen PC or laptop which does not have a Wacom digitizer - please contact the manufacturer if there is doubt about this
• The licence string is invalid, e.g. it has expired or has characters missing or added (please paste it into https://jwt.io to check its validity)
• The new style long licence string is being used with an old release of the SDK which only supports the old style short string. The long JWT licences are only supported from release 3.19.0 onwards.
• You are trying to run your application over Remote Desktop or Citrix and the signature pad isn't being forwarded over the network.
  For further information please see Use Citrix for signature capture
• You are using a virtual machine which isn't forwarding the signature pad data to the virtual operating system
• Your touch-screen PC or laptop does not have a Wacom digitizer and you are trying to capture a signature from an external Wacom pen device such as a DTU or Intuos
• You are trying to connect to a Wacom STU pad which is operating serially (e.g. 430-V or STU-540 in serial mode) without first applying the correct configuration settings

Solutions

1. Install the latest version of the Signature SDK and insert a valid licence string as described at How to install a license.
   A production licence for the Signature SDK (Lite version) can be obtained from the GETTING STARTED.md document on GitHub.
   If you do not wish to upgrade to the latest release of the SDK then it is possible to continue using the old style short licence. Please raise a Support Ticket to obtain one.
2. Ensure that you are using a signature capture device (digitizer or tablet) manufactured by Wacom
3. If you are using Remote Desktop ensure that the pad data is being forwarded over the network (see the Remote Desktop FAQ above)
4. If you are using Citrix make sure that the signature pad is supported - see Signature Devices supported on Citrix
5. If you are using a VM make sure that the signature pad is being successfully redirected to it - not all VM software does this automatically
6. If you have a touch-screen laptop, PC or tablet and you are trying to capture a signature from an external Wacom pen device rather than from the touch-screen itself then the Signature SDK or sign pro PDF is likely to fail because it will by default try to capture from the touch-screen.
   It will fail in trying to do so because the touch-screen is not Wacom compatible and therefore a special paid licence is required.
   The solution is to use the wtCintiq registry setting
7. If you are trying to capture a signature from an STU operating in serial mode make sure you have made the necessary configuration changes first. If applicable please see also Using the 540 with sign pro PDF in serial mode.