wifi 5ghz ssh wan connections

SSH WAN connections through 5Ghz WiFi hang after/at password entry (channel 0: open confirm rwindow 0 rmax 32768) on an Intel 8260 (rev 3a) card connecting to an RT-AC66U on 380.69_2 firmware. From a room a short distance from my router (with 4 out of 5 bars on wifi 5Ghz), I cannot make a WAN...