Why this picture rejected?

HINT:  Find another subject to photograph.  Adobe Stock already have millions & millions of perfect red roses plus every other flower you can think of.   With so much competition in the flower category, it will be very hard to get accepted much less sell anything.

Get creative.  Have a relevant concept and story to tell.  Start by photographing people in authentic surroundings.  Look at emerging trends & technologies  -- solar & wind power, nutrition, healthcare, construction, medicine, education, travel, etc...  Consider recent events. This time last year, the big selling images were of people wearing COVID-19 masks. 

Hi @Saji5EF7,

I agree with @RALPH_L, the picture is completely out of focus.

This extract should be crisp sharp and detailed, but in addition, you also have heavy colour noise:

If you are new to stock, you should consider these resources: https://helpx.adobe.com/stock/contributor/tutorials.html
Please read the contributor user manual for more information on Adobe stock contributions: https://helpx.adobe.com/stock/contributor/user-guide.html
See here for rejection reasons: https://helpx.adobe.com/stock/contributor/help/reasons-for-content-rejection.html
and especially quality and technical issues: https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html

Hi @Saji5EF7, it is simply not in focus.