The Washington Post and MSNBC both report that Lt. General Charles Flynn who is the brother of the disgraced ‘lock her up’ Lt. General Michael Flynn was one of the key Pentagon officials who refused to authorise the deployment of National Guardsmen as the 1/6 insurrection of Capitol Hill escalated.
https://www.msnbc.com/rachel-maddow/watch/wapo-meeting-on-military-response-to-trump-riot-included-mike-flynn-s-brother-99773509543Steven Sund the Chief of the Capitol Police said he tried six times to call for reinforcements but was blocked. He also claims to have joined a conference call with Pentagon officials and asked them to deploy the National Guard and was told no by Lt General Walter E. Piatt the director of the Army Staff - even after informing them that shots had been fired inside the Capitol.
Army spokesmen initially denied that General Charles Flynn had been in that conference room or played any role in refusing to deploy the National Guard, but according to the WP those denials are untrue, and General Charles Flynn was indeed in that room.
https://www.washingtonpost.com/national-security/flynn-national-guard-call-riot/2021/01/20/7f4f41ba-5b4c-11eb-aaad-93988621dd28_story.htmlIt was already known that Congressman Hoyer the democratic leader who was barricaded behind locked doors and Maryland Governor Larry Hogan who was in phone contact with him were unable to get multiple calls to the Department of Defense returned as the mob rampaged through the Capitol.
There is also an interview with Army Secretary Ryan McCarthy at the head of this CNN clip in which explains that he had to run from his office and down a corridor to seek authorisation to deploy after almost 90 minutes of confusion and delay. “Far too close to a disaster” as he observes.
https://www.youtube.com/watch?v=xhrKSXBQxWg&t=413s