Started over recently. Owyn won't let me in the first fight after signing up at the Arena. Tells me I'm not in my raiment, though I'm wearing the one he gave me. Downloaded latest patch from this site but didn't change it.

Try saving and reloading, exiting and re-entering, un-equip and re-equip the rainment, search the nearby cupboards for identical ones and try them all.

Lol, now all of a sudden I have the exact same problem and no idea how to fix it. Help?

If you are on PC I assume there's some type of console command. Maybe try wearing a different raiment, just get it from the cabinet.

I've tried some from the cabinets as well, no luck. AFAIK, there is no appropriate console command, I checked the UESP.

Post your load list. Using anything that changes the Raiment?

Oh, Hey You! Thanks for constantly helping me out.

Load order:

Oblivion.esm
Kvatch Rebuilt.esm
Better Cities Resources.esm
cssBase.esm
CM Partners.esm
MiddleEarth.esm
ShieldOnBack.esm
MERP Data.esm
MathFunctions.esm
Oblivifall Master File.esm
TamrielTravellers.esm
UnnecessaryViolence.esm
TOTW.esp
Unofficial Oblivion Patch.esp
DLCShiveringIsles.esp
Unofficial Shivering Isles Patch.esp
Better Cities .esp
Natural_Habitat_by_Max_Tael.esp
Natural_Water_by_Max_Tael.esp
Akatosh Mount By Saiden Storm.esp
Bedrollsanyone.esp
bnmDLTIC-1-6.esp
ClocksOfCyrodiil_BC_OBC_OC_OCLR_Vanilla.esp
Spell Delete And Item Remove.esp
Vows and Covenants.esp
Improved Hotkeys.esp
DLCHorseArmor.esp
DLCHorseArmor - Unofficial Patch.esp
DLCOrrery.esp
DLCOrrery - Unofficial Patch.esp
DLCVileLair.esp
DLCVileLair - Unofficial Patch.esp
DLCMehrunesRazor.esp
DLCMehrunesRazor - Unofficial Patch.esp
MaleBodyReplacerV4.esp
DMRangerArmor.esp
XSPipeMod.esp
cidnothump.esp
DLCThievesDen.esp
DLCThievesDen - Unofficial Patch.esp
DLCThievesDen - Unofficial Patch - SSSB.esp
Ivellon.esp
BravilSeaDomes.esp
Kvatch Rebuilt.esp
LetThePeopleDrink.esp
LostSwordOfTheAylied.esp
LostSwordOfTheAylied - OBSE Add-On.esp
MountainShack.esp
WOTFH_1.3.esp
DLCBattlehornCastle.esp
DLCBattlehornCastle - Unofficial Patch.esp
BattlehornCastleEnhanced.esp
DLCFrostcrag.esp
DLCFrostcrag - Unofficial Patch.esp
Knights.esp
Knights - Unofficial Patch.esp
Castle_Knightstone.esp
RTT.esp
The Lost Spires.esp
Natural_Vegetation_by_Max_Tael.esp
DecoratorAssistant with OBSE v1.1.esp
Kyoma's Journal Mod.esp
Kobu's Skip Intro Mod.esp
MidasSpells.esp
Faster Spells.esp
SigilStoneSelector.esp
Better Enchanting & Spellmaking Readme.esp
Denock Arrows.esp
SW01Plus.esp
CuteElf11.esp
_Ren_BeautyPack_full.esp
CM Partners.esp
CM Partners Special NPCs.esp
CM Partners NPC.esp
CM Partners More NPCs.esp
CM Partners Marker NPCs.esp
CM Partners Extra NPCs.esp
bgBalancingEVCore.esp
bgMagicEV.esp
bgMagicSpellTomes_for_WryeBash.esp
bgMagicItemSigil.esp
bgMagicBonus.esp
bgMagicEVAddEnVar.esp
bgMagicEVPaperChase.esp
bgMagicAlchemy.esp
bgBalancingEVOptionalClasses.esp
bgIntegrationEV.esp
Better Cities - Full City Defences.esp
Better Cities SKINGRAD.esp
Better Cities BRAVIL.esp
Better Cities ANVIL.esp
Better Cities - Ruined Tail's Tale.esp
Better Cities CHORROL.esp
Better Cities CHEYDINHAL.esp
Better Cities LEYAWIIN.esp
Better Cities - No LEYAWIIN Flooding.esp
Better Cities BRUMA.esp
bgMagicEVShader.esp
bgMagicShaderLifeDetect.esp
bgMagicLightningbolt.esp
Viconia.esp
MERP Armoury Chest.esp
MERP Travel Spells.esp
MERP Patch.esp
MELJMoriaArea2.esp
Abriael_Human.esp
Encumbrance100.esp
CT-Backpacks.esp
ShieldOnBack_1C.esp
Alternate Script Effect Icon.esp
1HweaponOnBack.esp
Visually Enchanted Paralyze by Agesofb.esp
ClaimThatInterior.esp
Arch_Mages_Robe_Enchanted-2185.esp
TheOubliette.esp
Vypers Arrow Spells-SI V2.esp
passive_wildlife-1945.esp
TTB.esp
Banes DB Mask Placer True.esp
SamVimes's Feint Death.esp
Lynges Unlimited Death Reload Time.esp
RAEVWD Cities.esp
RAEVWD Imperial City.esp
Quest Award Leveller.esp
Quest Award Leveller - Vile Lair.esp
Lost Paladins of the Divines.esp
Quest Award Leveller - Knights of the Nine.esp
Disenchant.esp
Quest Award Leveller - Mehrunes Razor.esp
RAEVWD New Sheoth.esp
Adonnays Elven Weaponry.esp
fwDropGold.esp
Enchantment Enhanced.esp
Solace.esp
Villages1.1.esp
UnnecessaryViolence.esp
Universal_Armor_Stands.esp
Wood Bows and Leather Armors.esp
MOBS SI.esp
TOTWcamp.esp
TOTWfurn.esp
FenrirTheWolf.esp
Duke Patricks - BASIC Script Effect Silencer.esp
Crowded Roads Revisited.esp
aaaJNF-&-DS-Pirate-Isles-Beta.esp
Walkabout.esp
Oblivifall - Losing My Religion.esp
ElsweyrAnequina.esp
TamrielTravellers.esp
TamrielTravellersItemsVendor.esp
TamrielTravellerAdvscript.esp
TamrielTravellersFactionAll.esp
ShiveringIsleTravellersFriendlyFactions.esp
VyperSMETG.esp
AzuraStarfix.esp

probably UV. you must eccuip the arena ring in your inventory, had the same problem also

This seems to have been the problem. I am now reigning Grand Champion. Thanks Gavril!

you're welcome i had the same problem. 2 times actually. stupid me. i had first spend a whole day trying to figure out the problem then i finally did a week later with new character i totally forgot it again :-p