I have a Galaxy S9+ and happens only to one work contact. It mutes his text immediately when he messages me or Even calls me His text will mute. I have done everything recommended from deletion of conversations to deleting the app and reinstall days later. To removing the contact and putting him back in days later I even removed app again while his profile was deleted. I unlinked him from every aspect I could find a tag in my phone to him. Text messages about him, facebook, pictures, emails, his girlfriends account, I even tried to put his profile back in as a different name with limited information so it looks like someone else unfortunately had to keep his number, he does work with me so I could not eliminate him entirely from work tags etc. But wow how far do I have to go to keep his messages from mute. It seems to be attached to his number but Verizon tech says that it's not possible. Any new ideas would be appreciated. It does not mute his ring tone from calls or messenger on facebook. Just message plus. So I do realize it could be the app. It's went past annoying to now I just really need to know how to fix it and why it is happening and what causes it.