I'm having trouble entering the Pokemon Tower after obtaining both the Silph Scope and Rainbow badge. Whenever I try to enter, I get stopped with the same "I believe this place is not safe for you" message.
If it helps any; after I defeated Erika, I lost to the man outside of the gym with the insane Pikachu, then went to the south-west exit of Celadon and spoke to the police officers to clear them out before heading to Lavender Town.