I have not been able to open DTTG on my iPhone recently. Sometimes I can but more often than not it seems to be freezing. This morning I have been trying for 40 mins to restart my phone, open DTTG, swipe up on the opened window to restart DTTG, but it is not working. Sometimes I see a completely black screen. At others, the last file I had opened. Any recommendationss on what to try next?