'unbounded' occurs when change a set of input values

Hi, everyone
I am solving a sdp problem. When I input the first set of values, cvx works well and I get a correct result; but, I change the input value, cvx turns out to be ‘unbounded’, both sdpt3 and sedumi has been used.Who can tell me the reson?

Perhaps because with the changed input values, the problem is unbounded.

Because you haven’t provided any information about your problem, or what the changes to the input values are, we can’t assess whether there might be some other explanation.