Matplotlib doesn't work well with threads. So if you're using Matplotlib you should wrap your code with locks as shown in the snippet below. This Matplotlib bug is more prominent when you share your app apps since you're more likely to get more concurrent users then.
```python
  from matplotlib.backends.backend_agg import RendererAgg
  _lock = RendererAgg.lock
with _lock:
    fig.title('This is a figure)')
    fig.plot([1,20,3,40])
    st.pyplot(fig)
  ```
All apps are hosted in the United States. This is currently not configurable.
