validation failed with custom textures

I’m getting an error when trying to launch session:

AssetLog] /MyProject/Custom_assets/Texture/Wall_Spec : Non-cinematic texture is too big. It is 4583x6478. Use LODBias to reduce its size to 2,048 or lower. (FortValidator_Textures)

I tried using resize import texture data, but no luck. It didn’t seem to do anything at all. Not sure what LODBias is actually.
Diffuse: 1.1 MB
Normal: 5.3 MB
Spec: 1.3 MB
Which isn’t out of the ordinary compared to the rest of the textures in the game. Funny thing is, the session was working until I saved a copy.

edit:

After reducing the size of the texture, the error went as follows:LogValkyrieValidation: Error: Found disallowed object type /CRD_PlayerSpawn/Materials/M_EnemyRangeVisualization.M_EnemyRangeVisualization, Referenced by:Content/__ExternalActors__/Airport_start2/D/Z8/DKI3W2XVG9I7IZ41KW39TJ.uasset, Plugin mount point:/MyProject.

LogValkyrieValidation: Error: Found disallowed object type /Game/Creative/Devices/DaySequence/Materials/MI_CP_Device_DaySequence_Placed_01.MI_CP_Device_DaySequence_Placed_01, Referenced by:Content/__ExternalActors__/Airport_start2/B/24/94GFGQNT762IIZJF3R2A9C.uasset, Plugin mount point:/MyProject.

LogValkyrieValidation: Error: Found disallowed object type /Game/Creative/Devices/SkyDome/Materials/MI_CP_Device_SkyDome_Volume_Placed_01.MI_CP_Device_SkyDome_Volume_Placed_01, Referenced by:Content/__ExternalActors__/Airport_start2/B/24/94GFGQNT762IIZJF3R2A9C.uasset, Plugin mount point:/MyProject.

LogValkyrieValidation: Error: Actor (Player 1 Spawn Pad) of Class (BP_Creative_Player_Spawner_Prop_C) referenced Disallowed Object (/CRD_PlayerSpawn/Materials/M_EnemyRangeVisualization.M_EnemyRangeVisualization)

LogValkyrieValidation: Error: Actor (Day Sequence Device) of Class (BP_DaySequenceModifier_Device_C) referenced Disallowed Object (/Game/Creative/Devices/DaySequence/Materials/MI_CP_Device_DaySequence_Placed_01.MI_CP_Device_DaySequence_Placed_01)

LogValkyrieValidation: Error: Actor (Day Sequence Device) of Class (BP_DaySequenceModifier_Device_C) referenced Disallowed Object (/Game/Creative/Devices/SkyDome/Materials/MI_CP_Device_SkyDome_Volume_Placed_01.MI_CP_Device_SkyDome_Volume_Placed_01)

UEFNValidation: Error: Found disallowed object type /CRD_PlayerSpawn/Materials/M_EnemyRangeVisualization.M_EnemyRangeVisualization, Referenced by:See below for asset list, Plugin mount point:/MyProject.

UEFNValidation: Error: /MyProject/Airport_start2.Airport_start2:PersistentLevel.BP_Creative_Player_Spawner_Prop_C_1

UEFNValidation: Error: Found disallowed object type /Game/Creative/Devices/DaySequence/Materials/MI_CP_Device_DaySequence_Placed_01.MI_CP_Device_DaySequence_Placed_01, Referenced by:See below for asset list, Plugin mount point:/MyProject.

UEFNValidation: Error: /MyProject/Airport_start2.Airport_start2:PersistentLevel.BP_DaySequenceModifier_Device_C_UAID_D8BBC1DA4EE6967F01_2067784695

UEFNValidation: Error: Found disallowed object type /Game/Creative/Devices/SkyDome/Materials/MI_CP_Device_SkyDome_Volume_Placed_01.MI_CP_Device_SkyDome_Volume_Placed_01, Referenced by:See below for asset list, Plugin mount point:/MyProject.

UEFNValidation: Error: /MyProject/Airport_start2.Airport_start2:PersistentLevel.BP_DaySequenceModifier_Device_C_UAID_D8BBC1DA4EE6967F01_2067784695

LogValkyrieSummary: Project MyProject failed to update

LogValkyrieActivityTracker: Warning: Upload -> Fail Activity: MyProject - Project validation failed

LogValkyrie: Unable to play: Validation failed

LogValkyrieActivityTracker: Warning: Upload -> Fail Activity: UploadProjects - All uploads failed with errors