Error in force field typing with the AMBER FF

Hello

Currently I am trying to calculate the DPD parameters for a solution of a flavonoid (quercetin). For that I will recur to molecular dynamics, but after

building the molecule and choosing the AMBER force field in the discover program, an error occur when I try to optimize my molecule.

The error says that the typing engine failed to calculate the force field type   and charge for 3 atoms (figure attached). Also, even if I manually specify the types, the error message still appears and states that the same atoms aren't typed.

How could I surpass this problem?

best regards