TITLE: GCN CIRCULAR NUMBER: 29700 SUBJECT: GRB 210323A: Nanshan/NEXT optical upper limit DATE: 21/03/23 23:09:33 GMT FROM: Dong Xu at NAOC/CAS S.Y. Fu (NAOC), Z.P. Zhu (NAOC, HUST), X. Liu, D. Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report: We observed the field of GRB 210323A (Gropp et al., GCN 29699) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations automatically started at 22:03:49 UT on 2021-03-23 (i.e., 91 s after the BAT trigger), and 3x40 s, 4x60 s and 12x90 s frames were obtained in the Sloan r-filter. No optical source is detected in our stacked image at the XRT position (Gropp et al., GCN 29699), down to a limiting magnitude of r~20.4, calibrated with nearby PanSTARRS stars.