You can get this message for a variety of reasons. For example, if you send messages containing blocked extensions (*.pif) or even certain types of URL's (i've been able to get messages blocked simply by sending a link to a PHP page on Facebook). Those are the most common reasons for the problems.
However, more recently I did have this problem happen to me for unexplained reasons for quite some time. Signing in and out helped for about 3 minutes. Are you doing any heavy downloading or uploading on your connection? This can potentially cause the problem, although its unlikely. You can check the .NET Messenger Service Status for by
clicking here. It should also be noted that the current release version of Windows Live Messenger is
8.1 and NOT
8.5. If you are not using the release version, then you need to downgrade to it to ensure maximum useability. This problem is not connected to Messenger Plus! Live.
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