Issues with Authorising Make Integration (via Platform Applications)

I'm trying to setup my Clickfunnels 2.0 workspace with Make.com via OAuth2.0. When inputting the OAuth2.0 Client ID and Client secret codes, it doesn't allow authorisation. I get a "We couldn't establish a connection" error. Spoke to technical support who advised I speak with developer support instead. Would be appreciated for some guidance, not sure if this is an account access issue or something else.