Loaded plugin FancyDrop v2.9.2 by FastBurst
Exception while calling NextTick callback (ArgumentException: An item with the same key has already been added. Key: GunRoll_Sub_Medium)
at System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) [0x000c1] in <fb001e01371b4adca20013e0ac763896>:0
at System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) [0x00000] in <fb001e01371b4adca20013e0ac763896>:0 n, 0b/s out
at Oxide.Plugins.FancyDrop.ExportLootSpawn (Oxide.Plugins.FancyDrop+ExportData expData, LootSpawn lootSpawn, System.Int32 level) [0x000c1] in <f380635290044234a37dc5ffb40c133e>:0
at Oxide.Plugins.FancyDrop.ExportLootSpawn (Oxide.Plugins.FancyDrop+ExportData expData, LootSpawn lootSpawn, System.Int32 level) [0x000ce] in <f380635290044234a37dc5ffb40c133e>:0
at Oxide.Plugins.FancyDrop.SetupLoot () [0x000a7] in <f380635290044234a37dc5ffb40c133e>:0
at Oxide.Plugins.FancyDrop.<OnServerInitialized>m__0 () [0x00000] in <f380635290044234a37dc5ffb40c133e>:0
at Oxide.Core.OxideMod.OnFrame (System.Single delta) [0x00051] in <ec05e0208c9149bba43236ca58fea105>:0
Saved 38,199 ents, cache(0.05), write(0.01), disk(0.01).
Saving complete

This is a brand new server. which i started using rust server manager...

same error here

Read the documentation under Special Note

FastBurst

Read the documentation under Special Note

I am getting the same error too,   Also found the special note, i reloaded it, still same thing.  Deleted the Config and the Data file, Still same thing.

You need to unload the plugin - then upload that datafile, then reload the plugin.