Comment by trickstra

It sometimes happens if you create account from a suspicious IP address, such as VPN or shared computer at school or cafe. They are trying to prevent account takeovers and fake accounts when some dormant users left weak passwords and got in a leak somewhere. But Facebook is also sometimes a bit too proactive in banning new accounts, because they use this as an opportunity to extract more information from you - you can only unban the account by providing phone number, scan of your ID card etc.. That suits them so they like banning more.