We have had a small number of clients who are experiencing random MT4 disconnects that do not reconnect until the MT4 terminal is restarted. In troubleshooting the issue we have verified the remote broker’s trading server is online when experiencing the issue.
We’ve found that when the bug is encountered, re-entering the password to your account has no effect. The MT4 terminal is dead and will not re-login until you restart the terminal.
It appears this is likely an MT4 application bug since the release of version 830. We have found and compiled these threads where there are mentions of a disconnect bug that may have started with MT4 build 830 and continues in build 840. So far there is no known fix.
We encourage you to report this to your broker’s support and you may need to reference some of the above threads for evidence that others are experiencing the same issue.
*Update July 1, 2015 We received a report today that this may be exclusive to Wallstreet Asia and/or Volatility Factor EAs. These EAs are using external DLL that may be causing the issue. Recommendation is for clients to contact the EA’s developers and request a fixed version. We’ve not been able to confirm this yet however.