This is a client side issue (doesn't mean other clients will have it too), reason for the issue for now unknown, If you can't connect to server through server browser try to use "direct connect":
The Update console window should then continue to run and install ArmA3 ((DEV or STABLE) version to the target directory as defined in the.Steam will have automatically sent you an email with this validation code, which you then need to input at the command prompt.Just after logging into Steam, the console window will hang and ask for a validation key.
Run the #Arma3server_steamcmd_example.cmd file.
Create an #Arma3server_steamcmd_example.cmd file and save it to D:\Games\ArmA3\A3Files.
(This will download and install the required steam files to your custom steam directory)