Frozen loading screen

While playing Co-op campaign with Mousey488, the loading screen didn’t show up at the end of a mission, instead it went black and never went back. The mission played smooth and cutscene worked just fine but it wouldn’t switch from one mission to the next without getting stuck on black screen until I restarted Halo and manually started the next mission. Mousey is relatively new to Halo 5 and I am helping her get started but this REALLY spoils someone’s experience of a game, especially for the first time ever playing the campaign. HELP!