Artwork errors

I’m running krypton 17.3 on 2nd gen amazon fire tv. when looking at my logs I saw
“NOTICE: Metadata and Artwork module -> Rate limiter active for omdbapi.com – delaying request with 1 seconds- Configure a personal API key in the settings to get rid of this message and the delay”
Just above this notice there is always multiple errors like:
“ERROR: DoWork – Direct texture file loading failed for special://masterprofile/thumbnails/….”
I saw there was an update available for the movie data base, I updated that and still got the same error.
I tried to search the forums but could not really find an answer, matbe I searched with the wrong keywords.
Any ideas what is wrong and how I can fix it?
Thanks