LTC6269 output oscillate

hi

I am using a LTC6269 as the attached pic for a DC circuit and it oscillate on output by 600KHz around the DC output value.

for CF i found some calculation on datasheet and used 0.5pF , 1.0pF , 2.0pF , 10pF but the problem still exist.

i need to have resistors in Mega Ohms range so i used:

R & RF = 50 MOhms

R & RF = 10 MOhms

R & RF = 1 MOhms

oscillation exist on all