Cannot upload an avatar for a friend. What am I doing wrong?

This is the error it gives me

Failed to build the Avatar, check logs for more details
UnityEngine.Logger:Log (UnityEngine.LogType,object,UnityEngine.Object)
(wrapper dynamic-method) UnityEngine.Debug:UnityEngine.Debug.LogError_Patch1 (object,UnityEngine.Object)
VRC.Core.Logger:LogError (string,string,UnityEngine.Object)
VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__150:MoveNext () (at ./Packages/com.vrchat.avatars/Editor/VRCSDK/SDK3A/VRCSdkControlPanelAvatarBuilder.cs:3140)
System.Runtime.CompilerServices.AsyncVoidMethodBuilder:Start<VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__150> (VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__150&)
VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder:BuildError (object,string)
VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__142:MoveNext () (at ./Packages/com.vrchat.avatars/Editor/VRCSDK/SDK3A/VRCSdkControlPanelAvatarBuilder.cs:2892)
System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1<System.Exception>:Start<VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__142> (VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__142&)
VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder:HandleBuildError (System.Exception)
VRC.SDK3A.Editor.VRCSdkControlPanelAvatarBuilder/d__140:MoveNext () (at ./Packages/com.vrchat.avatars/Editor/VRCSDK/SDK3A/VRCSdkControlPanelAvatarBuilder.cs:2777)
UnityEngine.UnitySynchronizationContext:ExecuteTasks ()