Routing by region looks simple and fails in small ways. The rule is correct on paper and the leads still land in the catch-all.
1. Names and codes are different values
If state and country picklists are enabled, Salesforce keeps a code (GB) and a label (United Kingdom). An entry written against one never matches a lead holding the other.
2. Free text is not a list
Without picklists, leads arrive with UK, U.K., United Kingdom and England. Each is a separate value, and an entry catches only the ones it lists.
3. A region is not a country
An entry for "EMEA" tests nothing unless a field holds it. Regions must be a field you fill, or a list of countries in the entry.
4. The field is blank
A lead with no country matches no country entry. It goes to the catch-all, or to the default owner if there is none.
5. An entry above it takes the lead first
Salesforce stops at the first entry that matches, so a broad entry high in the list starves every narrower one below it.
Check it yourself
SELECT Country, COUNT(Id) FROM Lead WHERE IsConverted = false GROUP BY Country ORDER BY COUNT(Id) DESC
SELECT COUNT() FROM Lead WHERE IsConverted = false AND Country = nullThe first shows every spelling your leads use. Compare each against the values in your entries. If picklists are enabled, group by CountryCode too.
Have it checked every night instead.
Routing Forensics connects as a read-only user and checks this, and the rest of your routing, against your real leads. Register interest and you will be first to get a free health report: what is leaking, where, and what it is worth.
The free scan cannot see this one: it reads assignment rules, flows and queues only. Connected, it is checked every night.