“Hi ,” is a variable that resolved to nothing. There are three reasons it happens.
1. No fallback
The prospect has no value for that field, so it renders empty.
Fix: give every variable a fallback.
{{first_name|there}} · {{company|your team}} · {{role|your role}}
The pre-launch safety check flags variables without fallbacks. It is worth not skipping.
2. The variable name does not match
Tags are lowercase with underscores and must match exactly. {{firstName}} and {{firstname}} are not {{first_name}}. Only seven tags exist, and there is no company or job title tag. Doreach flags anything else as an unsupported merge tag before launch.
Fix: use the variable picker in the editor rather than typing them, and check custom names against the import mapping.
3. Imported data is missing or shifted
A CSV where a column was mapped to the wrong field, or where many rows are simply blank.
Fix: open Prospects, filter for empty values in the field, and check the mapping. Reimport if columns were shifted. The preview on the mapping screen exists to catch this.
Preview before launching
Every message step has a Preview that renders against real prospects from your audience. Step through 10–15 of them. Blank and odd values are obvious immediately, and this costs a minute against a mistake that goes to hundreds of people.
If it already went out
Pause the campaign so more do not follow. The messages cannot be unsent.
In practice a plain “Hi,” reads as slightly terse rather than obviously automated, so it is rarely worth apologising for and drawing attention to. Fix the fallback, preview, resume. If a message went out with something worse, such as a literal {{headline}} in the text, a short human correction to those specific people usually lands fine.