Xcorr questions

Dear Obspy team,

I have 4 seismic events so I´d like to do a relative location using
xcorr_pick algorithm proposed in obspy, so I did the following
procedure (also following the literature)

- selected certains events.
- I filtered them to have a clear P wave (1 to 10)
- I cut 1 sec. around the P wave (with slice method).
- Did the same for all events.
- I defined the times like the example in the tutorial.
- I gave t_before=0.01 , t_after=0.8 , cc_lag= 0,55
- then this warning tells me: xcorr_pick_correction raise
Exception(msg) Exception: Trace 0 starts too late.

here is my code:
import os, sys
import obspy
from obspy.core import read
from obspy.signal.cross_correlation import xcorr_pick_correction

os.chdir(r'E:\+0niN0_shallowEvs\2014_lloja\141001_06h08\SIV_Z')

#Ev1 y Ev2

S1=read('141001T0610_SIV_Z.sac')[0]
S2=read('141001T0701_SIZ_Z.sac') [0]
t1=obspy.UTCDateTime('2014-10-01T06:10:5.0 Z')
t2=obspy.UTCDateTime('2014-10-01T07:02:48.5 Z')
dt, coeff = xcorr_pick_correction(t1, S1, t2, S2, 0.01, 0.8, 0.55, plot=True)

Attached the waveforms too, thank you for the time and suggestions.
Best Regards
Tonino

141001T0610_SIV_Z.sac (896 Bytes)

141001T0701_SIZ_Z.sac (896 Bytes)