I get msg "unexpected transmission problems beyond our control'. when trying to efile from MAC. They call it a "technical hiccup". Anyone know what I should do?

Full msg: "Your Transmission Didn't Go Through
TT was unable to send your return to the Intuit Elec Filing Ctr, for the following reasons: Due to unexpected internet transmission problems beyond our control, your returns were NOT received by the Intuit Elec Filing Ctr.  You should re-file your returns now.  Looks like we've had a technical hiccup.  Try e-filing again.  If that doesn't work you can print your return and file by mail.  

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I called support, first guy said to try different browsers, clear cache, etc. Did that (was Chrome, tried Safari & Firefox), same result. 2nd call lasted over 90 minutes. She had me update Mac OS to new version just released that day. Also had me switch from WI-FI to direct Ethernet cable. Same results, on phone over 90 minutes. I will be switching to a different solution than TurboTax next year.