Can't connect to PYNQ-Z2 board

Hi all,
I have set up my PYNQ-Z2 board for a few months and it works just fine. However, last week, after I connected it to a peripheral (to be exact, a DSP board with SPI communication), Jupyter froze (unfortunately, I did not screenshot the situation) and I can no longer connect my PYNQ-Z2 board to Jupyter, which stays in “can’t reach this page” like the following figure.

I have a few questions:

  1. What could be the problem and how do I fix it?
  2. Is there any way to get my files stored in the SD card?