error downloading data from tutorials running within docker container

[HumphreyWang]

Thanks for helping me open thie issue!

I just began to learn pycbc recently, and it seems that I always get the error which indicates 'I failed to open the url to downnload the data', like this example from tutorials:

%matplotlib inline

import pylab

m = catalog.Merger("GW150914")

# Get the time series data around GW150914 from Hanford
# 'ts_han' is a pycbc.types.TimeSeries object which contains
# gravitational-wave strain in this instance and has metadata
# such as the start time, and sample rate.
ts_han = m.strain('H1')

# And now livingston
ts_liv = m.strain('L1')

# We can see how much data was returned and its boundaries
# Note: All times are given in seconds since the GPS time epoch
print("Duration: {}s Start: {} End: {}".format(ts_han.duration, 
                                              int(ts_han.start_time),
                                              int(ts_han.end_time)))

# We can directly plot the time series as follows
pylab.plot(ts_han.sample_times, ts_han)
pylab.ylabel('Strain')
pylab.xlabel('Time (s)')
pylab.show()

then I got this:

I don't know if it is caused by the firewall because I am in China. But it didn't work even if I open the VPN, while those codes can work very well in Colab.