Here the py-bt (gdb) py-bt Traceback (most recent call first): <built-in method draw_markers of matplotlib.backends._backend_agg.RendererAgg object at remote 0xfff47394b0> File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/lines.py", line 2888, in draw File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/artist.py", line 50, in draw_wrapper return draw(artist, renderer) File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/axis.py", line 555, in draw 'matplotlib.ticker.Locator') File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/artist.py", line 50, in draw_wrapper return draw(artist, renderer) File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/axis.py", line 1419, in draw elif not visible: # something false-like but not None File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/artist.py", line 50, in draw_wrapper return draw(artist, renderer) File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/image.py", line 388, in _draw_list_compositing_images extra_height = (out_height - out_height_base) / out_height_base File "/home/picca/matplotlib-3.5.0/build/lib.linux-mips64-3.9/matplotlib/axes/_base.py", line 4106, in draw Python Exception <class 'UnicodeDecodeError'> 'ascii' codec can't decode byte 0xc2 in position 2280: ordinal not in range(128): Error occurred in Python: 'ascii' codec can't decode byte 0xc2 in position 2280: ordinal not in range(128)