error bars with dataframe and pandas

[Hucky]

Found the mistake. I did
[pyhton]fig, (ax1) = plt.subplots(1, 1) ....[/[pyhton]]

and then later again
[pyhton]fig, (ax1) = plt.subplots(1, 1) ....[/[pyhton]]

Now I changes the second subplots ax1 to ax2 and everything works fine.
Thank you for your help.