Hello Mani,
After some trials, I think I have got the issue. Please go through the below-mentioned steps:
1. Check WP-admin>>WooCommerce>>Settings>>Accounts
If you see that the checkbox against the option” Enable registration on the “My Account” page”, is unticked, please tick, save and see if the problem is solved.
2. Check Wp-admin>>WCMp>>Pages
If you see an error against the options like “Vendor Dashboard”, Shop Settings etc then you have a different problem here. Maybe the default pages created by WCMp were deleted manually on this WordPress install. Please login to your PHP MyAdmin and visit the wp_options table. Search for the option_name
a. dc_product_vendor_plugin_page_install
b. dc_product_vendor_plugin_page_installed
and delete both of them. Then deactivate WCMp plugin and when you reactivate, that error should be gone on the Pages list.
Let me know if that helps.
Regards,
Sandeep