As @FolkLondon mentions, email can be a bit of a minefield when it comes to trying to resolve these issues.
There's a few things to consider, depending on your set up:
- If you're using your own SMTP server, QuickFile is unable to track bounces (which means if an email is returned for whatever reason, we are unable to show this)
- We do however try our best to check when an email is opened, but this can vary depending on your client's set up. Not all of them will trigger this, and some will even trigger it automatically.
- If you're using QuickFile's default mail setup (which is via Amazon using the email@example.com address), Amazon will track bounces for us and report back
- If an email does bounce, depending on the bounce, a block may be put in place for a period of time. If an issue does crop up, this will be shown on the client record
You can view the blocks, fails and sends on the Email Sent Log (I believe you've already found this, but in case you haven't it's found by going to Account Settings >> All Settings >> Email Sent Log. This feature does require a power user subscription.
To check an individual email address, if you view the client, this is shown beneath their record, as highlighted in email complaints & bounces article.
I hope that helps, but if you're still stuck, please send me a private message with the email address in question and I'll take a closer look for you.