What happen in lately development certificate?

I created and downloaded a development certificate today, It alway show "Unable to install. Constrained by the certificate." when installing app signed with the certificate.

but It installed same app properly if signed with the certificate made the year before last.

What happen in lately development certificate?

Do check that you have all UID's in the sis are from the Symbian signed account you got the certificate for. Also do re-check that you are really including the IMEI of the device in the certificate as well.

Solved, UIDs ans IMEIs is no problem. it request UIDs saved.