Hello @Shalini Toopran ,
in your case, the IoT Hub devicelist in the Azure portal was not shown and some generic exception text is shown.
Although this is not the behavior we like to see, I have come across this a couple of times in the past. There are even Q&A questions on this forum dedicated to this issue.
In the past, this issue was Azure Portal related and was fixed automatically within a couple of hours, without further action needed.
I cannot recall if this was also an issue using the Azure IoT Explorer tool or the CLI or the programmable API.
Next time, keep calm and just wait for a couple of hours ;-) Try the Azure IoT Explorer first.
You can always submit a support request (under 'Help + support' in the Azure Portal) if this takes more time and the other ways to access devices is not available.