Can anybody tell me what a black tick inside a grey circle means on FB Messenger? I've had this several times with various contacts over the last few months when I've tried to send a message (especially when it is more than a couple of lines) but can't find an explanation as to what it means anywhere. I'm guessing it means that the recipient hasn't read my message but I don't know why. The symbol never changes, and so my messages are apparently going unread. Although I've googled it, there doesn't seem to be an answer anywhere as to what a black tick inside a grey circle means. I use an iPhone 12 Mini.
I'm hoping more savvy mumsnetters may be able to help me with this. Thank you in advance :-)