A phone number has to be valid before Bookboost will send an SMS or WhatsApp message to it. If a guest is not receiving those, an invalid number is the usual reason, and this explains what makes one invalid.
Numbers are checked against the international numbering rules for the country they belong to, rather than against anything specific to Bookboost, so a number rejected here would be rejected by most other systems too.
How a number is checked
Two passes, in order.
The number as written. It is checked exactly as it arrived, for example 015223433253. If that passes, it is valid and nothing else happens.
The number plus a country code. If the first pass fails, Bookboost adds a country code taken from the country on the guest's profile, for example DE for Germany, and tries again.
If the guest has no country on their profile, the second pass cannot happen and the number is marked invalid. This is the most common cause: a local-format number with no country to infer the code from.
Leading zeros
A number beginning 00 is read as a +.
00660891234567 is valid, and means +660891234567.
0660891234567 is invalid.
000660891234567 is invalid.
Bookboost also tidies the number before checking it, so a repeated country code such as "+66 +66 0891234567" is reduced to one before validation rather than failing on the duplication.
Fixing an invalid number
Store numbers in international format. A number written as +49 15223433253 validates regardless of what else is on the profile. This is the reliable fix.
Add the guest's country so the code can be inferred for local-format numbers.
Correct it at source. If the number is synced from your PMS, fix it there. See Editing a guest profile for which fields you can change in Bookboost.
What this does not do
Valid does not mean real. Validation checks that the number is correctly formed for its country, not that anyone answers it.
It does not tell you whether the number takes WhatsApp. A valid mobile number may have no WhatsApp account behind it.
The result cannot be overridden. A number that fails the check cannot be marked valid, including by support.
It does not check landlines against SMS. A valid landline number is still a landline, and an SMS to it will not arrive.
What to do next
To find every guest you cannot currently reach, build an audience with the Reachable filter set to exclude. See Audience filters: reachability.
Getting help
Open Help at the bottom of the left menu and choose Talk to Us, or email support@bookboost.io.