I am playing in the Classic ERA servers (Vanilla) @Blizzard
Below is the error I get every time I log in.

Date: 2022-07-31 11:08:19
ID: 1
Error occured in: Global
Count: 1
Message: ..\AddOns\SpartanUI\modules\AutoTurnIn.lua line 890:
attempt to index field 'AutoSelectLoot' (a nil value)
Debug:
[string "@SpartanUI\modules\AutoTurnIn.lua"]:890: BuildOptions()
[string "@SpartanUI\modules\AutoTurnIn.lua"]:730:
SpartanUI\modules\AutoTurnIn.lua:729
[string "=[C]"]: ?
[string "@bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua"]:70:
...AddOns\Bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua:65
[string "@bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua"]:527: EnableAddon()
[string "@bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua"]:540: EnableAddon()
[string "@bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua"]:630:
...AddOns\Bartender4\libs\AceAddon-3.0\AceAddon-3.0.lua:615
[string "=[C]"]: LoadAddOn()
[string " local loadType = Stubby.GetConfig("Informant", "LoadType")
if (loadType == "always") then
LoadAddOn("Informant")
else
Stubby.Print("Informant is not loaded. Type /informant for more info."); -- ### _TRANS
end
"]:3: in main chunk
[string "=[C]"]: RunScript()
[string "@stubby\Stubby.lua"]:914:
Stubby\Stubby.lua:907
[string "@stubby\Stubby.lua"]:927: f()
[string "@stubby\Stubby.lua"]:738: EventWatcher()
[string "@stubby\Stubby.lua"]:958: Events()
[string ":OnEvent"]:1:
[string ":OnEvent"]:1
Locals:
None
AddOns:
Swatter, v2.5.6773 (SwimmingSeadragon)
AtlasLootClassic, vv2.4.3
AtlasLootClassicData, vv2.4.3
AtlasLootClassicDungeonsAndRaids, vv2.4.3
AucAdvanced, v2.5.6733 (SwimmingSeadragon)
AucFilterBasic, v2.5.6759 (SwimmingSeadragon)
AucStatHistogram, v2.5.6761 (SwimmingSeadragon)
AucStatiLevel, v2.5.6765 (SwimmingSeadragon)
AucStatPurchased, v2.5.6762 (SwimmingSeadragon)
AucStatSimple, v2.5.6763 (SwimmingSeadragon)
AucStatStdDev, v2.5.6764 (SwimmingSeadragon)
AucUtilFixAH, v2.5.6766 (SwimmingSeadragon)
BagBrother, v
Bagnon, v9.2.0
Bartender4, v4.11.2
BeanCounter, v2.5.6767 (SwimmingSeadragon)
CharacterStatsClassic, v3.8.3
DBMCore, vee0b66f
DBMStatusBarTimers, vee0b66f
DBMVPVEM, vbffd391
Details, v
DetailsTinyThreat, v
Enchantrix, v2.5.6768 (SwimmingSeadragon)
EnchantrixBarker, v2.5.6769 (SwimmingSeadragon)
Gargul, v4.3.2
Grid2, v2.0.44
Grid2LDB, v2.0.44
Grid2RaidDebuffs, v2.0.44
IceHUD, v1.13.13
Informant, v2.5.6770 (SwimmingSeadragon)
NovaWorldBuffs, v2.28
SlideBar, v2.5.6771 (SwimmingSeadragon)
SpartanUI, v6.0.39
Stubby, v2.5.6772 (SwimmingSeadragon)
TitanClassic, v1.3.1.11401
TitanClassicAmmo, v1.3.1.11401
TitanClassicBag, v1.3.1.11401
TitanClassicClock, v1.3.1.11401
TitanClassicGold, v1.3.1.11401
TitanClassicLocation, v1.3.1.11401
TitanClassicLootType, v1.3.1.11401
TitanClassicPerformance, v1.3.1.11401
TitanClassicRegen, v1.3.1.11401
TitanClassicRepair, v1.3.1.11401
TitanClassicVolume, v1.3.1.11401
TitanClassicXP, v1.3.1.11401
TranqRotate, v2.2.3
WeakAuras, v3.7.16
WeaponSwingTimer, v7.1.1
BlizRuntimeLib_enUS v1.14.3.11403
(ck=675)

Fixed in alpha builds