I am not in any guild and all my characters are guildless, yet I too am getting wow51900319 disconnection.
That may be something different. This thread is specifically about large guild and communities and disconnections. You may want to start your own thread, as that is the generic disconnect.
What Zungar said is correct. The wow51900319 is a generic common connection error. The guild issue is something that we ran across and confirmed. It happens specifically with larger communities and higher ranks.
If you’re not in a guild, the information is not relevant to your issue, instead we’ll need to look at potential connection issues or somethings character specific issues can happen that we’ll need to look into.
To get a better look into this, could you include a WinMTR file until the problem occurs for 10 to 15 minutes. Copy and paste the text file created and paste it between two ~~~ like so:
~~~
WinMTR Here
~~~
If you have issues pasting here, use Pastebin and post the end of the link. (ie. 123456 for pastebin.com/123456)