For the past couple of months, every so often, Skype will not notify me that I have received a message. It is worth noting that use Skype for Mac on my laptop and on my iPhone. Both are up to date and have notifications enabled properly. I have uninstalled and reinstalled several times. I even have Skype Preview in use on my laptop. I can tell I do not receive some messages because I'll check a conversation every so often, and I can see that my message has been read, but no message has been sent back. Then I'll check skype on the web and there, a message will finally come, often marked at an earlier time. For example, my message will have been read at 10:00 and my friend will immediately send me a message, but I will not receive a notification of it until I exit and open it again, often later, as I have not been informed of an incoming message. When I exit and re-enter Skype on my laptop, the new message now appears.
I will note that this issue is intermittent, so it doesn't always happen, but it has been happening much more lately. I don't know what to do.