Hi Rahul Nain,
Please note that this issue is related with the use of Paid Memberships Pro, not with the use of your theme. You can deactivate this plugin to make your website accessible to everyone or set the default role of PMPro to everyone. However, it’s best if you try to reach the plugin authors as they will be more informed and better suited to help you.
To go further, we invite you to post your request on their support forums: paidmembershipspro.com/support/
We remain available for all support requests related with the use of your theme.
Best,