I have the answer to this and needed to post because it was no where to be found. You need to ask Siri to read your messages.
I had that issue, had no unread messages but still came up as 3 unread.
Easiest way to deal with this is saying ”Hey Siri” ”read my messages”.
She will read the ones that are unread that you may have missed and problem will often solve this issue.
Confirming that having Siri read those messages aloud also worked for me! Happy New Year!
Why does my iPhone say that do not have any voice messages when there are voice messages?
Omg thank you so much. Worked like a charm.
Thank you. Siri read the 5 messages I couldn’t find. I had one unread message for years.
This worked! Thanks!
Miracle! It's been several YEARS that I had one unread message and was unable to find it and mark it as read.
Thank you very much for this tip!
iPhone and iPad showing unread messages even though I’m not seeing any unread message
