I have already created several au's and there have been cases where “Fetch branches” has not worked for various reasons. However, since you cannot enter a branch via “Add,” I would recommend creating an SR in UC at this point.
There is either something wrong with the SmartConsole, the API, or whatever.
The only thing I would do before the SR (if you haven't already) is install the latest R81.20 SmartConsole. If it's up to date, as I said —> SR
and now to something completely different - CCVS, CCAS, CCTE, CCCS, CCSM elite