The default WordPress URL can't be parsed as an RSS URL on OnlySocial, to resolve this, you need to create a proxy URL using Google Feedburner. Follow the guide below.
Creating an RSS Proxy URL with Feedburner
Go to https://feedburner.google.com/ and log in with your Google account.
Click the Create Proxy button.
Paste your default WordPress RSS URL (e.g.,
https://example.com/feed).Enter a Title for the Proxy.
Click the Create button.
Copy the RSS Proxy URL that you just created.
Adding the RSS Proxy URL to OnlySocial
Go to OnlySocial and click RSS Schedules from the Main Menu.
Click the Add New button.
Paste your Feedburner RSS Proxy URL in the provided field.
Click the Add button.
To further configure your RSS feed, See our RSS Setup Guide