When a guest did not get a campaign, the first thing to establish is which of two things happened: the campaign never tried to send to them, or it tried and failed on every channel. The causes are different, and so is the fix.
The campaign was never sent to them
Work through these in order.
No contact details on the profile. Check the guest has an email address or a phone number. Without either, there is nothing to send to.
Wrong guest type. The campaign may be targeting a different guest type to the one on this profile.
The guest is not in the audience. Open the campaign's audience and confirm the guest matches its filters.
There is a duplicate profile. See below.
Missing consent. If the campaign requires consent and the guest has not given it, they are skipped.
It tried to send and failed on every channel
Invalid email address.
Phone number problem. The number may be invalid, unavailable, a landline, roaming, or the guest may not have WhatsApp installed.
Duplicate guest profiles
If the same guest exists twice, the other profile has probably received the campaign instead.
Match and Merge handles most of these automatically, but duplicates can still appear with OTA reservations, where the profile is later updated from your PMS with the guest's real email address. When that happens, search for a profile using the OTA guest email rather than the real one.
Getting help
If none of these explains it, open Talk to Us in the left menu of the platform, or email support@bookboost.io. Tell us the campaign name, the guest name or reservation ID, and which of the two situations above you have ruled out.