That's just a shortcode. Can we see the page that it stopped working on? That will give us the information as to why. I'm thinking it could be as simple as the plugin maybe needs to be updated or it accidentally got disabled/deleted.
If you need to get the form up asap, you could always just use the embed code as that does not rely on the plugin and you can just put on your page(s) as needed. Personally I usually recommend that over the plugin and shortcode as there are advanced embed options not available through this type of implementation.
That definitely explains your error. Your embed code that is there has an error in it causing a parsing error that shows up in the console:
I would open a ticket with Hubspot in case it is an error in the plugin causing this to see if they can look into your site since the code is injected in the shortcode. However, you may be able to put the raw embed code into your site to have the form load. But that all depends on your access and wordpress setup whether it is done through the backend, or whether this has to be done by a developer.