Timing failure on internal paths

Your original screenshot is missing the most important bits. 0 to 8 ns is just setting the stage. 8 to 15 is where the real action is.

Also, you seem to be contradicting yourself. If it is working fine at 164 without any constraints and you were able to run it at 190 with the constraints, then how come your screenshot is showing a failure (-1.5 ns setup slack) at 172 MHz (1/5.814 ns)?

Post the view of the second half of the timing path and the drawing in the "extra fitting information" tab.