Often that would be a fair comment. However the OP didn't ask "fix this code", but "what could cause this error". As it happens I know the context for this question and showing the code is not practical. The error is being generated in called code that includes 3rd party modules and there may be thousands of lines of code involved.

Update Oh, and the failure depends on transient external conditions that are somewhat unknown and not easy to reproduce.

Update and just to be clear, the script in question is Perl, but it runs a Python script that generates the error. OP and I couldn't figure out how Perl could be generating the error.