Calendar Base Error

Message: Missing or wrong parameter. The event you are looking for could not be found.

Note: Please verify your URL parameter: tx_cal_controller[uid]

URL:http://gruene-brandenburg.de/termine/cal/event//tx_cal_phpicalendar/2019/12/11/aktiv_sein_und_mitgestalten_wie_kann_ich_mich_in_der_stadt_oder_kommune_einmischen/