called USCIS for 485 status

My 485 was submitted on May 15. When I called USCIS last week to check
the NC status, the call was transferred to an IO, but need to wait for more
than 30 min. I could not wait for such long time at that day and just gave
it up. When I tried to call again yesterday and today, it said that "this status can not be found at this time in this automatic system..." and did not transfer to IO. But I can check the status of I-131 and I-765, which means the system works fine. What's going on with I485? anyone has the same problem?

Thanks a lot!