"no value" printed for the field contains String value

Hi

I have created an alert that has a message text as below;

@atomic_failed_jobs_alert@{{.Group}}@wonum={{ index .Fields “wonum” }}@{{.Level}}

When alert rises, message text is;

@atomic_failed_jobs_alert@group=ISQ2ISUS,host=YYYY,jobname=FTP@wonum=u003cno valueu003e@CRITICAL

wonum is a field with String values like AAA, BBB.

How can I get value of wonum field?

value & wonum columns are fields;

Thanks.