VIDEO: Miguna rejected by IEBC after giving signatures in wrong format
County returning officer Joseph Mele said he presented 2,000 signatures in JPEG, as opposed to the Excel format.
Miguna, who wants to take over from ODM Governor Evans Kidero, dropped James Gathungu as his running mate and picked Karen Wangenye.
He had unveiled Gathungu, 24, saying this was a spirited bid to incorporate youths into leadership. He noted this is lacking in Kenya.
Twelve aspirants, including Kidero and Nairobi Senator MIke Sonko (Jubilee), are expected at the stadium today to present their documents ahead of the poll.
Six are being sponsored by parties while the rest are running as independent candidates.