Assertion failed

Hello! Thanks for the tool. We have encountered with the following error when use with **Gait Optimization flag enabled** for **HYQ robot**

towr_ros_app: /home/robotic01/catkin_ws/src/towr/src/phase_durations.cc:86: virtual void towr::PhaseDurations::SetVariables(const VectorXd&): Assertion `durations_.back()>0' failed.

How can we solve the issue?
Thanks in advance!