The channel, which is a favourite of President Trump, is also suspended from making any money on YouTube.
The suspension will last a week, during which time no new videos can be put up. To make money in future, the channel must rectify the issues.
YouTube is attempting to clean up its platform and has also removed QAnon and pizzagate-affiliated accounts.
Pizzagate is a conspiracy theory about a paedophilia ring involving members of the US Democratic Party operating out of a Washington pizza restaurant, while QAnon believers think President Donald Trump is waging a secret war against elite Satan-worshipping paedophiles in government, business and the media.
In a statement about OANN, YouTube said. "Since early in this pandemic, we've worked to prevent the spread of harmful misinformation associated with Covid-19.
"After careful review, we removed a video from OANN and issued a strike on the channel for violating our Covid-19 misinformation policy, which prohibits content that claims there's a guaranteed cure."
YouTube operates a three-strikes policy - any second violation in a 90-day period would result in a two-week suspension. A third strike would lead to a permanent ban.
OANN must also reapply to the YouTube Partner Program if it wants to make money from its videos.
YouTube, along with rival social media firms Facebook and Twitter, is under intense scrutiny for the amount of misinformation and hate speech that finds its way onto its platform.
It said that it had removed 200,000 videos related to dangerous or misleading Covid-19 information since February.
This week, a group of Democratic senators wrote to YouTube chief executive Susan Wojcicki, urging it to remove all election outcome misinformation.
YouTube has removed adverts and added a warning label to a video falsely declaring that President Trump had won the election.
President Trump has tweeted that OANN and other news sources which question Joe Biden's election victory are a "great alternative" to Fox News.