Your DAC is not corrected correctly, according to its datasheet.
1) The reference voltage input should go to pin 8 (not 11),
2) The output should go from pin 11 (not 8) directly (not via a cap) to the opamp inverting input,
3) The non-inverting input of the opamp should be grounded (at least to AC),
4) There should be a feedback connection from the opamp output to pin 9 of the DAC.
1) The reference voltage input should go to pin 8 (not 11),
2) The output should go from pin 11 (not 8) directly (not via a cap) to the opamp inverting input,
3) The non-inverting input of the opamp should be grounded (at least to AC),
4) There should be a feedback connection from the opamp output to pin 9 of the DAC.