DMC provided incorrect pricing and can't honor it after deposit

I booked some personal travel with a high-end DMC that my host agency recommended. It took several weeks to get the first itinerary. We made some minor changes to the dates, but accepted the itinerary by paying the $20K deposit. The itinerary came in at $54K, which was over the budget I provided of 30-40K.

A week or so after booking, the DMC's CEO emailed me to say they had quoted the wrong price for one of the lodges and that we would need an additional $11K.

I am pretty sure the advisor I worked with at the DMC is brand-new, and I was one of their first clients.

Is this error something that E&O insurance would cover? I did reach out to the host agency but they haven't gotten back to me yet.