Tracking with Royal Mail (UK) not working.

Hello. I add tracking of Royal Mail carrier. I can track it on Royal mail website or 17track.
But when i track on your plugin. It say: Tracking data is not available now. Please come back later. Thank you.
I try with other carrier for other order: (EX: SF Express). It working well.
I put tracking order link. And try this number: NU118831196GB
Then you can try with royalmail site: https://www3.royalmail.com/track-your-item#/tracking-results/NU118831196GB

Please help. I try with aftership and trackingmore. Same prolbem.
Thanks.