Whats up with Snapchat ? [I Love Internet]

My sister uses Snapchat to text her boyfriend he said yesterday her name hasn't been coming up when she texts him he said all his notifications are on. She wouldn't block him or report him she loves him too much to do that. He's got perfect internet he said it just started this yesterday. His name is showing up for her. Anybody else having this problem ? How can he fix this?