Mail App Confounding Messages!

[Mr. Monsieur]

Hey folks!

Every now and then (it's becoming more common, actually) Mail will note that a new message has come in, but when I click on the new message, I find that it has replaced the new message with an old message from my Inbox (or a folder). In order to read the actual new message, I have to go online to my email provider to read it. Really. Annoying.
Does anyone have any suggestions as to how to fix this?

Thanks in advance!

 

[Mr. Monsieur]

Really? No thoughts? Argh...it's unbelievably annoying...alas.

 

[miles01110]

Never experienced that problem. What mail service are you using? Gmail? What kind of account is it?

 

[Mr. Monsieur]

I use Fastmail.Fm...but I'm pretty sure the problem is with Apple's Mail app, as when I go online I'm able to view the message as it's meant to be. It's weird...it has been working properly for years...and I haven't changed anything...