TITLE: GCN CIRCULAR NUMBER: 22667 SUBJECT: Fermi GBM trigger 545979055/180421202 is not a GRB DATE: 18/04/21 14:36:22 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 545979055/180421202 at 04:50:50.91 UT on 21 April 2018, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles."