Until last week, we were using the API key after converting it to a base64 value but as the following:
Authorization: Bearer ${sink.base64ApiKey}`
However, today, all our API calls started failing - but they started working when we changed the above to:
Authorization: Basic ${sink.base64ApiKey}`
Is there any reason why this suddenly changed or started working?
Hello @Satyavrat_Bondre
Welcome to the Freshworks community 
It is possible this is due to a deprecation warning issued a long time ago, because I can see our sample apps have always demonstrated using the latter approach (Basic authorization).
Allow me to invite you to check out the example here.
We will meanwhile check internally to find out when this change was planned. Thanks for reporting it.