Warning message with opsv.plot_defo() command

[miguelvega]

Hello everyone!
I'm trying to use the openseespy.postprocessing.ops_vis lib in order to plot the deformed shape of a building after modeling a pushover analysis, but I'm getting this message:

WARNING nodeDOFs DOF group null
---------------------------------------------------------------------------
OpenSeesError Traceback (most recent call last)
<ipython-input-31-a32aca9f275f> in <module>
----> 1 opsv.plot_defo()

C:\ProgramData\Anaconda3\lib\site-packages\openseespy\postprocessing\ops_vis.py in plot_defo(sfac, nep, unDefoFlag, fmt_defo, fmt_undefo, interpFlag, endDispFlag, fmt_interp, fmt_nodes, Eo, az_el, fig_wi_he, fig_lbrt)
1587 This usually happens when translational DOFs are too small\n\n""")
1588
-> 1589 _plot_defo_mode_2d(0, sfac, nep, unDefoFlag, fmt_defo, fmt_undefo,
1590 interpFlag, endDispFlag, fmt_interp,
1591 fmt_nodes)

C:\ProgramData\Anaconda3\lib\site-packages\openseespy\postprocessing\ops_vis.py in _plot_defo_mode_2d(modeNo, sfac, nep, unDefoFlag, fmt_defo, fmt_undefo, interpFlag, endDispFlag, fmt_interp, fmt_nodes)
777 if nen == 2:
778
--> 779 ndf = np.shape(ops.nodeDOFs(ops.eleNodes(ele_tags[0])[0]))[0]
780
781 # truss element plot_defo
OpenSeesError: See stderr output

I've ploted others small models with out problems, but it's not the same story with this model . Could anyone please tell me what I can do to solve this issue?