We are experiencing the exact same issue.
Our customers are complaining that they are not receiving our emails.
The range of public HubSpot IP addresses that have a ‘bad reputation’ have been flagged as spam and prevent our emails from being received by our actual clients.
The ‘solution’ HubSpot provided us with is to purchase a ‘dedicated fixed IP address’ at a very high cost.
HubSpot is at the origin of a conceivable known issue by using public IPs of low reputation and decides to make clients pay for the solution at such a high price. How is that possible?