-Variety reports, due to a disagreement with Grammy producers over which songs she would perform. Ariana Grande won't only not be performing on Sunday, but she won't attend at all.
-Ariana felt insulted after producers refused to let her perform "7 rings." A compromise was eventually reached, after they said she could perform a medley that included 7 things. Ariana approved until producers told her the second song was of their choosing.
-A source close to Ariana has said "such stipulations were not imposed on other performers"