I have Wordpress multisite. I want the user who is registered from any of my network site to not be able to login to other network site.
For example, just now, if any user is registered on site1 then that user will login to site2 also with site1 login credential, so is there any way that user should not login to other sites?
It depends on how you chose to differentiate your sites (users). IMO, you have two options:
Use subdomains:
site1.domain.com, site2.domain.com ... siteN.domain.com
This approach will require server configuration but it won't require you to do any development on the application side.
Use custom URI paths:
domain.com/username1, domain.com/username2 ... domain.com/usernameN
This approach will require additional development at the application level
