Why is the gain of antenna array infinite?

I am using a custom antenna imported from HFSS but the problem is that when i use this antenna to create an array and find its gain, the gain turns out to be infinite. Anybody knows why this problem is occurring?

[Star Strider]

Are you comparing it to a reference array, such an isotropic (vertical) antenna or simple dipole?

[Honglei Chen]

Could you provide a bit detail on the pattern as well as the script how you computed the gain? Is it possible for you to share your pattern?

[Haris Mahmood]

I have attached the file exported from HFSS which i am using to create a custom antenna in Matlab and create an array using the custom antenna. Its a simple dipole. To calculate the gain i am using the phased.arrayGain system object of MATLAB.