Hello @Rajesh Kotwani ,
Thanks for reaching out.
I could see your tenant M365x659986.onmicrosoft.com has not been deleted and your custom domain is still active in the same tenant, therefore I'm interested as to what steps you referred to delete your tenant? I would recommend you to repeat tenant deletion as explained here and then adding your custom domain to your new tenant.
If you can can't delete a directory through the Azure Management Portal and here are some causes.
Hope this helps.