Hi @Pyae Phyo Maung ,
is this a Free Azure Subscription? If so it might be because the free period of 30 days is over?
At the end of the 30 days the Free Azure Subscription will be disabled until you switch to the PayAsYouGo payment model.
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten