[whpalmer4]

Same answer applies: contact Omni support directly and they will help you out or get you a refund.

If Apple has done its part of the work correctly, there should be no way any requests OmniFocus makes of the network stack should disrupt your network connection, any more than sending packages should cause UPS trucks to crash. There are thousands of people syncing OmniFocus in the same manner you are trying to do without trouble. There is also a large number of ways in which a network can fail mysteriously in a manner that is very difficult to understand without considerably more visibility of the situation than we have here. There's a reason why so many networking gurus have gray hair :-)