Welcome to the Q&A Forum

Sir , Thank you for replying, i will explain step by step what i have done; Old site: https://www.selldealsmango.com/ New site: https://www.dealsmango.com/ first i have remove all pages from my old site, than only home page left, i then remove all the data from home and on that blank page i posted the new site URL. by clicking on that old site URL you will know what i am trying to explain. but i am using canonical tag  for old site also. than i have generated XML site maps of both sites and uploaded on google search console. after that i request for indexing and duplicate canonical error occurs. in 2nd step i have put 301 redirect from old site to new site and than again i have request for indexing but error remain the same.