User access denied for '%' in 5.6 (no replies)

MySQL 5.6

I executed this grant for a new user:
grant select on testdb.* to 'user1'@'%';
But this does not allow them to get connected?

I had to grant this before they could connect but I don't want my users to have this much access?
grant select on *.* to 'user1'@'%';

How do I allow access but limit the user to just a single user DB?


thx,
rick_806