Monitor the viewer logs while in world.

Send a direct IM from one avatar to another

Note in the viewer logs on the receiving end:

2024-11-20T17:48:05Z INFO # llmessage/llcorehttputil.cpp(275) LLCoreHttpUtil::HttpCoroHandler::onCompleted : Possible failure [Http_403] cannot POST url 'https://simhost-0a32da980e865990c.agni.secondlife.io:12043/cap/ca40190b-dd25-512f-0b89-42a749c1e4b5' because Forbidden

2024-11-20T17:48:05Z INFO # llcommon/llsdserialize_xml.cpp(409) LLSDXMLParser::Impl::parse : LLSDXMLParser::Impl::parse: XML_STATUS_ERROR parsing:You cannot join chat

2024-11-20T17:48:05Z WARNING #ChatHistory# newview/llimview.cpp(645) chatterBoxHistoryCoro : 17322f01-5b63-01b6-1788-a64d79fe7da0: Bad HTTP response in chatterBoxHistoryCoro, results: {'error_body':'You cannot join chat','headers':{},'message':'','status':i1,'success':0,'type':i403,'url':'https://simhost-0a32da980e865990c.agni.secondlife.io:12043/cap/ca40190b-dd25-512f-0b89-42a749c1e4b5'}

The viewer is requesting the chat history for this one-on-one direct IM chat, which will always fail because there is no session on the chat servers for direct IMs

Better fix: don't do that