Error when joining instance to availability group

Hi Team,

While setting up AG between SQL cluster instance in Primary and SQL standalone in DR, we are getting error 35250 while joining availability group' error in the last step. I tried to check on internet, there is few issues logged if accounts SQL service accounts are not domain account. In my case both service accounts on primary and secondary are domain account (using the same accounts to run SQL database engine on primary and secondary).

https://msdn.microsoft.com/en-us/library/ms366346(v=sql.120).aspx

Then i have added the machine accounts as well for primary and secondary replica servers (create login and grant connection)

Any other thing that i need to check to resolve this issue?

Regards