Hi, Sorry for the beginner's doubt, but why the system below doesn't work?

When I try to run, it returns an error:

Error: Equation without any variables revealed after application of replacements:
    0.0 = 0.0   Equation before replacements:
    0.0 = atan2(spring1.lineForce.lineShape.widthDirection[2] * spring2.lineForce.lineShape.widthDirection[3] - spring1.lineForce.lineShape.widthDirection[3] * spring2.lineForce.lineShape.widthDirection[2], 1.0)   Replacements:
    spring2.lineForce.lineShape.widthDirection[3] -> 0.0
    spring2.lineForce.lineShape.widthDirection[2] -> 1.0
    spring1.lineForce.lineShape.widthDirection[3] -> 0.0
    spring1.lineForce.lineShape.widthDirection[2] -> 1.0                                                      Error: Equation without any variables revealed after application of replacements:
    0.0 = 0.0   Equation before replacements:
    0.0 = 1.5707963267949 * (1.0 - sign(spring1.lineForce.lineShape.widthDirection[3] * spring2.lineForce.lineShape.widthDirection[3] + spring1.lineForce.lineShape.widthDirection[1] * spring2.lineForce.lineShape.widthDirection[1] + spring1.lineForce.lineShape.widthDirection[2] * spring2.lineForce.lineShape.widthDirection[2]))   Replacements:
    spring2.lineForce.lineShape.widthDirection[3] -> 0.0
    spring2.lineForce.lineShape.widthDirection[2] -> 1.0
    spring2.lineForce.lineShape.widthDirection[1] -> 0.0
    spring1.lineForce.lineShape.widthDirection[3] -> 0.0
    spring1.lineForce.lineShape.widthDirection[2] -> 1.0
    spring1.lineForce.lineShape.widthDirection[1] -> 0.0 Error: Equation without any variables revealed after application of replacements:
    0.0 = 0.0   Equation before replacements:
    0.0 = atan2(spring1.lineForce.lineShape.widthDirection[1], 1.0)   Replacements:
    spring1.lineForce.lineShape.widthDirection[1] -> 0.0

But when I try the following system with one fixed point, it works:

I tried to initialize the body properly in each system, but just the second one works. I know that there is some constraint issue but I can't see clearly why it doesn't work. I can imagine the system working mechanically but bringing it to multibody approach in modelica it still hard for me.

Follow attached both models.

OBS: Gravity vector is {0,0,-1}.

Attachments:

mass_bar.mo

mass_bar1.mo