The Welsh club have revealed the reasoning for the closure on Monday is due to 'appalling abuse and threatening behaviour'.
Support staff had been allegedly subject to abuse during the priority purchase period on Thursday.
Newport have since stated tickets can be purchased online but from 10am onwards tomorrow.
The club has reiterated it has a zero-tolerance policy which may result in stadium bans or legal action.
Newport booked their place in the FA Cup fourth round after beating Eastleigh 3-1 in their third-round replay.
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Aaron Wildig opened the scoring on three minutes, but Paul McCallum equalised for Eastleigh after half-time.
Though goals from James Clarke and Will Evans ensured Erik ten Hag's side will visit Rodney Parade on Sunday January 28.
Manchester United secured a 2-0 victory over Wigan, with Diogo Dalot and a Bruno Fernandes penalty sealing their place in the fourth round.
Speaking ahead of the tie, Newport boss Graham Coughlan believes it is the biggest clash in the club's history.
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"It'll be a hell of an occasion," Coughlan told BBC Sport ahead of the first-ever meeting between both the teams.
"It's a fourth round tie against Manchester United, for me the biggest club in this country, in Europe and in the world.
"I know some people would lean towards the fifth round game against Manchester City (in February 2019), but I'd say Manchester United all day long."
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