ABS printing problem in internal side

As you can see from the pictures there is a problem in the the inner side of the wall.
On the other hand the outer side of the wall is smooth.
Does anyone have any advice?

The basic printing parameters are:
Temp.: 225 degrees
Flow: 75%
Layer height: 0,105 mm
Retraction distance: 4 mm
Retraction speed: 110 mm/s