Spark 2.7.5 on OSX 10.9.5 blank screen

Hello, i have installed Spark 2.7.5 on my OSX 10.9.5. The application is opened normally, the first screen is appeared and i type my username, password and server. After that i check "login" and the next screen is blank and the application is not responding...

I tried 2.6.3 (12555) and it works with no problem (except of no notification when a new message arrives...)