Hi @mathahasy,
I would like to tell you that found out the cause of the issue and shockingly it was not from the plugin creators’s side. It was actually a hosting provider issue.
To be precise I had multiple entries in database tables in my database, like wp_users, wp_metadata etc.
Just by deleting the duplicate entries and configuring the database with wordpress properly I was able to get jetpack setup on my self hosted wordpress blog.
Let me know if I could help in any way.