Hi. I often get half a batch of rejections for this reason:
Issues to review and correct include the following:
Keywording language: The keywords must match the selected language.
Keywording order: Keywords must be ordered by relevancy, not alphabetically.
Title or Keyword compliance: Information must be relevant, not offensive nor violate copyright
I write everything in English, there is no spam in the keywords, everything is to the point. File ID: 553430302
Then you should check really your keywords. Maybe sharing the keywords and the title of one of your files here will help us to understand. We can't look into your refused assets.
bouquet of blue flowers, watercolor painting
flowers, bouquet, love, blue, heart, decoration, holiday, watercolor, floral, romance, beauty, concept, pattern, isolated, gift, white, invitation, celebration, blossom, valentine, decor, design, background, spring, card, romantic, beautiful, flower, illustration, greeting, plant, art, leaf, symbol, nature, element, graphic, shape, vintage, grow, tree, flora
Don't double plural and singular. Put only the singular.
I would put the singular as a keyword. Adding the plural version is unnecessary.