im trying to get car insurance for my 77 300D but when i enter my vin it keeps saying invalid vin. I have the title and an old insurance card from previous owner and entering the vin as it appears there and still does that. what to do?

__________________
1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)