We are getting 401 - unauthorized since yesterday. Is there anything changed on the API side?

We posting DELETE on the end point - 

https://api.unbounce.com/pages/<pageid>/leads/<leadId>

with header:

{'Authorization': 'Bearer <token>'}

This was working well for the last 4 years and all of a sudden starting getting 401 since yesterday. 

Thanks for any help on this from the API Team or any body experiencing this now.