The way the hashtag related feature works is by finding the similar hashtag to the last hashtag we wrote in the caption.
This related hashtag data comes from Instagram API.
Virol only processes existing data and displays it.
If the related hashtag results does not show up after clicking the related hashtag button, it could be that Instagram doesn't have related hashtag data to the hashtag we entered.
This is also often if we use too specific hashtags, branded hashtags, or a brand new hashtags.