The status “not available” displays when i check reservation availability between two stations what it means?

I have check reservation inquiry on erail.in for below query and view the seat availability status then it shows me below information table.

Now somebody explain me in below table what is the meaning of NOT AVAILABLE

TRAIN NUMBERTRAIN NAMEDATE (DD-MM-YYYY)SOURCE STATIONDESTINATION STATIONQUOTA CODE
9037AVADH EXPRESS16-01-2010VADODARA JNRATLAM JNGENERAL
S.NO.DATECLASS-SLCLASS-3A

116-Jan-2010, SaturdayNOT AVAILABLENOT AVAILABLE
218-Jan-2010, MondayNOT AVAILABLENOT AVAILABLE
320-Jan-2010, WednesdayNOT AVAILABLENOT AVAILABLE
421-Jan-2010, ThursdayNOT AVAILABLENOT AVAILABLE
523-Jan-2010, SaturdayNOT AVAILABLENOT AVAILABLE
625-Jan-2010, MondayNOT AVAILABLENOT AVAILABLE

boss kuch train mai minimum 500 km kay niche tickut nahi milti is liye not avalable batata hai kyuki varodara say ratlam 350 km kay aas pass hai aap 500 km kay uper wale station mai serch karo aap ko position jaroor batayega

aap ratlam ki jagah kota tak serch karo aapko positation bata dega

aur aapko fare bhi minimum 500 km ka hi lagega

Pavagadh Dahod Godhara Halol Kalol vadodara Ahmedabad Bolo Jai mahakali Maa ki Jay ho