Less Is Sometimes More
You would think that knowing someone’s exact date and place of birth would be helpful when looking for them on the census, but if you are drawing a blank, then start experimenting with leaving information out. After all, your ancestor may not have been sure themselves about their date and place of birth, or have given false information, and by specifying these details you are encouraging the subscription site to prioritise these factors in its results.
I had an ancestor who I could find in every census except 1871, because he was away from home and whoever filled in the census gave him the same place of birth as others in the household, even though he was born in another county. I only found him when I removed place of birth from the search. Play around with what you include and see what happens.