Hello,
1. The cURL error indicates your your webserver likely has a firewall, curl is disabled, something like that. This is a hosting issue- please discuss this with your host, as we cannot do anything to assist with this issue on our end.
Please let me know what you can find out form your host.
2 & 3: please go through these debugging steps THOROUGHLY and see if you can isolate these issues . DO the steps, please. Then we can know how to progress, depending on your results: https://www.wcvendors.com/help/topic/read-before-requesting-support/
4. That is the page title. Change the title of the page where you have the pro dashboard shortcode.
5. You can direct non-vendor members to the Pro dashboard page and they will see the Vendor Application ./ signup form.
You can then add or edit fields in your vendor signup for template if you wish to change it.
The template: wp-content/plugins/wcvendors-pro/templates/front/vendor-signup-form.php
-How to properly edit templates: https://www.wcvendors.com/kb/changing-vendor-templates/
-An example of how to add new fields: (you’d add tot eh vendors-signup-form.php instead of the store-settings.php): https://www.wcvendors.com/kb/custom-fields-to-shop-settings-page/