Google indexing issue but buyer need revision

[grantatrade2011]

Hello
My gig is about Adsense niche approved website creation. Site is completed and now there is domain mirror or seething else issue and google is not indexing pages, showing error in his google search console . He ask me to help I tried but failed to solve the issue . Now he is asking again ( 2nd ) revision to fix this issue, this is technically issue not mine.
What should I do now ? me wants from me to fix the error and index his website pages.