D-Link DGS-1210-28 factory reset

Have a problem with D-Link dgs-1210-28. Can’t get into web interface after reset.

I’m holding reset button about 20 sec (until power indicator blinking).
After that I’m able to ping default switch IP – 10.90.90.90, but nothing else: no connect to tcp port 80.

I’ve tried to use D-Link Network Assistant (DNA) app. And it automatically added my switch to list. But to perform any actions, it asks to enter Username and Password. But there is no any default Username and Password on it. Some basic credentials like admin/admin isn’t working.

Another confusing thing: after power off I should reset it again to be able toping 10.90.90.90

Any thoughts how to get this switch under control via web interface or DNA?