@eaglexk
Error 307 indicates you've been disconnected from the server, which can sometimes be for inactivity. When this happens, you should wait for a period of 15-20 minutes before attempting to login again. If you are repeatedly getting this error message please let us know.
@furiouslog
If you've been able to reproduce getting disconnected when practicing on the Precursor, you should open a bug report with customer support.