Hello, Vishnu
It can be due to conflict with a 3rd party plugin.
In order to identify the issue on your site, we kindly ask you to enable debug mode in WordPress, as per the instructions provided in the following link: https://wordpress.org/support/article/debugging-in-wordpress/. This will help us to determine what needs to be fixed.
Please provide temporary wp-admin and FTP access, so we can check the problem more deeply.
To provide wp-admin access, you can create a new user account with administrator role via the Dashboard, and provide us with the username and password via the Private Content area.
To provide FTP access, please contact your hosting provider for assistance.
We look forward to hearing from you.
Kind Regards,
8theme team