Blocking of undesirable voice over internet protocol (VOIP) communications is disclosed. A communication screening service initiates operations to block a threat posed by a VOIP communication upon receiving the communication from a gateway server. The communication may include an audio/video conversation and/or an audio/video conference. Next, metadata and content of the communication is analyzed to detect a threat, such as a scamming scheme and/or a phishing scheme, from a sender of the communication. A rejection of the communication is generated to disrupt the threat associated with the communication. The rejection is transmitted to the gateway server to prompt the gateway server to block the communication.