Hey Robich,
My problem is solved now. Actually, there was a problem at my ISP side, the cache was not cleared at their end. In fact, after number of failed attempts when I tried to switch my connection with another ISP (fortunately have two ISP connections) it immediately responded and my BB starts working perfectly as before.
Then for endorse my exploration again, I switch back the the 1st ISP and got the problem again.
Therefore, please try to check your ISP side as well.
Hope that will help.
Rashid Inam
https://www.adroitlogix.com