Invitation

Invitation is a weakness of vampires and hybrids, including Original Vampires. In order for a vampiric being to enter any house owned by humans, witches, werewolves, or (human) doppelgängers, they must be invited by the owners of the home.

Once invited, the vampire cannot be uninvited, unless the ownership of the house changes.

Revoked Invitation
While a vampire who has been invited into a house cannot technically have their invitation revoked, there is a loophole to this rule—if the ownership of a house changes, then the vampire will have to be re-invited by the new owner. If a vampire is desiccated or unconscious when the ownership changes the vampire will become disoriented and will begin to feel as though they are suffocating until they are able to flee from the house.

Vampires in a house that changes ownership will be pulled by an invisible force until they are out of the house, and they will need to be re-invited to gain entry.

Trivia

 * The idea that vampires need to be invited to enter homes or residences has different meanings, but the principle is mostly the same "Protection against undead".
 * In some stories, vampires can not enter homes because it is inhabited by living things, and it's like being underwater, murky and full of life.
 * The origin of inviting a vampire into a home is in the novel Dracula by Bram Stoker. It is mentioned that Dracula was always invited to the homes, causing suspicion about this feature because in those days, people of a high social class invited other people of the same class as a form of education and respect. Because Dracula looked, talked and moved like a person of high social statue, it was easy for him to gain an invitation into others' homes.
 * There are only a few known, non-magical, loopholes to boundary barriers against vampires. It has not been shown to be able to be broken through the use of magic.
 * First, it has been shown and proven on several occasions that one way to break the barrier for a vampire to enter owned property is to kill said owner of the property.
 * Second, humans can be compelled by vampires to be let in. (This is the closest use of 'magic' as vampires were created with magic).
 * Third, is to have the deed to the property made null through legal manipulations like Marcel did to the Mikaelson Compound
 * Forth, is to have imminent domain cast to make the property available to the public