How to solve this ?

MathWorks Account Unavailable - Technical Issue

Due to a temporary problem, MathWorks Account is unavailable. Try again later.

If this problem persists, contact support.

[Trent Northrop]

I'm having the same problem. Might be a server issue

Answer 1

[Walter Roberson]

You wait a bit. If the problem continues, contact Mathworks Support.

See also https://www.mathworks.com/matlabcentral/answers/222731-license-center-unavailable-technical-issue#answer_182159

Note: apparently you can get that message if you are attempting to contact the license servers but you have proxy or firewall problems.