Index out of range

[MSKantulu]

Hi,
I was trying domain adaptation using OpenNMT-py (version 3.5.1 ) on Google colab, and I came across an error on index out of range. I tried modifying my parallel data(Kannada-English) but could not resolve the same. Please find the error log and configuration details.
error_log.txt
Kn_En_DA_yaml.txt
train corpus 1: 100000 sentences
train corpus 2: 23985 sentences
validation set: 1000 sentences
please guide me as to how to resolve.
Thanks