Telegraf custom grok pattern can not parse (?! regexp predicate

In telegraf.conf tail plugin, writing custom grok pattern, can not parse (? ; but can work well if writing in ‘grok_custom_pattern_files’
But to regexp predicate : (?! , cant not work well even writing in ‘grok_custom_pattern_files’
On the whole, I use the good

Hello @basic_bl,
What is your data, what is your grok pattern, and what is your question exactly? I’m a little confused.