sums up what I suspect, but your post is too light on details to nail this one.
In short, it's a common issue and frustrates some that its part of curbing spammers.
Now here is a little mystery. I tried to reply to an email today and added an attachment. A NAV window popped up saying "...........your mail server rejected the message 554. Sorry the message is rejected here." I looked on Google for "554" and read some of the links but these didn't seem to help much. A techie friend suggested that there might be a phrase in the email that NAV didn't like.
The first thing I did was remove the attachment but that didn't make any difference.
So I started editing the email and sending extracts to myself. Eventually I discovered that if I left out one short sentance the email would send.
Is there an explanation?
Help, my PC with Windows 10 won't shut down properly
Since upgrading to Windows 10 my computer won't shut down properly. I use the menu button shutdown and the screen goes blank, but the system does not fully shut down. The only way to get it to shut down is to hold the physical power button down till it shuts down. Any suggestions?