If you're importing a podcast from Squarespace, you'll want to follow the instructions provided on their support website. From their support website:
In the Home Menu, click Pages.
Hover over your podcasting Blog Page title, and click the gear icon next to the title to open Blog Page Settings.
Click the Syndication tab.
Under iTunes / Podcasting Setup, click Edit Settings.
Scroll down to Change your feed URL.
Select Moving from Squarespace.
Enter your new Pinecast RSS feed URL in the box (you can find this on your Pinecast podcast dashboard).