Not getting boss drops?
World boss chests are once per boss a day.
Here is information on World Bosses: https://wiki.guildwars2.com/wiki/World_boss
Good luck.
The ground chest is once per boss per day PER CHARACTER. Run another character, get another chest. Run the same character, get naught. Since those are low level World bosses, it’s easy to run up a 2nd character and do them twice.
The bouncy chest on the right side is once per boss per day per ACCOUNT. That starts at level 39 (I think) and is guaranteed rare with a chance for exotic. It’s a good way to gear your character up with rare gear, as you don’t have to buy it, and you can sell the stuff you can’t equip and bank it, or use it to buy something you can equip. I never bought any gear since 4 drops a day will give you 1 piece to equip and in a couple of weeks you are full. Loot drops around your level, so as you level up you can replace the older stuff with newer.
Size of the zerg may also be an issue. I’ve seen players not getting the boss chest in large zergs because it seems that there’s a limit on how many players it tracks tagging the boss for damage in that first few seconds. Like I said, LARGE zergs.
RIP City of Heroes