Unable to connect to HA instance

I have been running HA now for a while now without major issues. Yesterday I got an ipad so I decided to download the HA app and try to set up HA on the ipad. Later I realize that I am now unable to connect to my Home Assistant instance on my computer. I unplugged the raspberry pi and replug it and when it reboots, I still get the message saying:
“unable to connect to Home Assistant, it is possible you are seeing this screen because your home assistant is not currently connected, you can ask it to come on line via the Remote UI Portal”

I try connecting through the Remote Ui Portal by signing in to nabu casa and when I select connect, I get the message: connection failed: no response from instance.
Please I would appreciate any help I can get.
Thanks.

Did you install the SSH add-on? If so, try SSHing on where you can use the command line to check the logs.

You may want to visit the Discord server and get more interactive help there.