To give us a reasonable chance of solving your problem, you'll have to give us a reasonable amount of explanation.
We're here to help but please understand that we can't see what you see. How do you find out that it's deactivated? Are there any error-messages? Can you post a screenshot? Have you done a forum-search for your problem? Are any of the sticky posts at the top of page 1 relevant to your situation? Are you referring to access using an email client or using webmail? What device(s) are you using? Do you have a VM Broadband account? What size feet do you have? Why do councils always put their refuse sites beneath flocks of seagulls? Did you put the cat out, and if so why was it on fire? Shall I go on?
Learning one day at a time how it works, breaks, and gets fixed. Use Kudos to show your appreciation, send Guinness to really show your appreciation :-) Mark answer as "helpful" only when the problem is solved. I do not work for VM... I work for peanuts.