Blurry print indicates either a non-SUPVAN label tape is installed or the print head is dirty.
First, ensure you are using only original SUPVAN label tapes. Non-original products cause poor print quality and may not be recognized.
If the tape is original, clean the print head. Turn the printer off, open the housing, and remove the tape roll. Gently wipe the print head with a cloth or cotton swab dipped in ethanol alcohol. Let it dry completely before turning the printer back on.