Tags are not updating in PGIM

We are using Freelance 900F, 2016 sp1 with PGIM (ver 5.1.2) through OPC. We configured few tags in PGIM the values are showing in PGIM and updating. But after few months later, now we want to configure more new tags in PGIM but we are facing a problem that the tags values are showing in PGIM but never updated new tags. The old tags are still working and updating. Can anyone suggest solution for this problem?

Regards