Is it acceptable to solicit answer from university?
If their own deadline has passed, yes, you can ask. Send a polite email to whoever is handling the admission. As long as you don't demand it, no one will take offence.

There are many reasons why you wouldn't have received an answer, but note that some institutions, as a policy, never notify rejected candidates (ESA is among the worst at this, they never tell, even the candidates that have been interviewed).

Best of luck.