Narayan not going to vaikunth

From the beginning and till today of DKDMD episodes,Narayan is still showing in shreesagar and not in Vaikuntha...why? But in other shows like om namashiva and om namo narayana,he was shown only in Vaikunth.Actually where's his real or actual residence?

first of all its ksheerasagar not shreesagar.
ksheera means milk and sagar means ocean.

so ksheerasagar is called "Ocean of Milk".
Lord Vishnu has two abodes one Vaikuntha and other Ksheera Sagar. Vaikunth is his permanent abode which is beyond material Universe. It is said to be the highest place for liberated souls and a place of eternal happiness and bliss.

Ksheera Sagar on the other hand is the highest place in "Material Universe" where VIshnu resides on SheshNag and manages the Universe from here. Since this is present in the material universe, its approchable by demigods who can visit ksheera sagar to seek Lord Vishnu's help in case of any turbulence in the universe.

Whats shown in DKDM is correct. Demigods indeed do visit KsheeraSagar not Vaikunth.