Issue was restored by Meraki on the 26th of January at around 20:45 H CET.There was a proprietary issue on their backend which began causing issues for clients that were only capable of using TLS1.0 or 1.1. Clients capable of using TLS 1.2 continued ...

We have the same issue with the Meraki Radius server and It's confirmed by the Meraki support desk that they have a global issue in their platform. They are working on a solllution with high priority.