I am quite sure the error occurred before I could claim any free gifts on day 1 day 2 of 6.1 release. Then on day 3, I was able to claim both the daily gift and 6.1 celebration gift. I still see the 6.1 celebration gift.
If it's from an On Line server source error then rebooting phone or uninstalling app won't do anything at all. We just need to wait until our devs get into it and fix up the issue