Hi @erhanevgin, have you tried a factory reset? A while ago I had the same problem, and to solve it, it was necessary to reduce the number of characters in the network name. Support explained why, but I don't remember exactly why.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
Please, if this post was useful, leave your kudos and mark it as solved.
