Hi Folks. I've yet to complete this mission (had 1 attempt last night but DCS crashed just as I Pushed!
I believe:
You will only get the TAD indication from JTAC once you complete the full JTAC contact: Check-in, Read Back, etc.
As far as I understand it, The Container is a no fly zone. Entering is an immediate failure. Form a couple of other threads it seems the Abort message may be a bug and can be ignored.
I will have another go tonight and see how I get on.
(I am pretty new to DCS and am by no means an expert, so apologies if this is incorrect/inaccurate!)
Update: Just had another go at the mission. I loitered at SP5 (Marshal) until confirmation that SA19s were down as brief states 'Only move into FEBA once area sanitized' then pushed in. At SP7 I checked in with JTAC and was given TAD target. I did get the Abort, no permission message but continued anyway, successfully taking out Arty with help from 2. I was given mission success, RTB message so checked out with JTAC and headed home.
I highly recommend using the PDFs that come with the campaign as they give more detail than the in-game brief and, with the map and line-up card, add to the immersion.