All teams roster are working except for these slugs : sixers && blazers
Client error: GET http://data.nba.net/v2015/json/mobile_teams/nba/2018/teams/blazers_roster.json resulted in a 404 Not Found response
I also try to with your tools :
http://nbasense.com/nba-api/Data/MobileTeams/Roster/TeamRoster#request-form-playground
Error: Could not retrieve the result at this time.
url in browser return empty page for those slugs too :
http://data.nba.net/v2015/json/mobile_teams/nba/2018/teams/sixers_roster.json
http://data.nba.net/v2015/json/mobile_teams/nba/2018/teams/blazers_roster.json
Thanks for your help