Hello Robert,
Please let me help you and, let me help you help us
IF your Yubikey is working as intended please keep it. As soon as you will have
ANY problem do the following:
go on
http://demo.yubico.comtry to authenticate the OTP and screenshot the technical details and send it to me via the forum and to the
support@yubico.com Ask via e-mail
support@yubico.com for a warranty replacement which will happen immediately by following the support's instructions.
I am asking you this because i would be happy to narrow down the issue you have been experiencing.
Your Yubikey can generate a very very very large number of OTP so you should not worry about that.
Thank you.