Cannot access anymore REST API interface through PHP with authentication

Wowza Streaming Engine
1

Hello,
after updating to WSE 4.8.19+4 I cannot access anymore REST API interface through PHP using WSE PHP Rest library.
Any request with authentication (basic or digest, cleartext or hashed password) returns this response: [“message”]=> string(40) “The request requires user authentication” [“code”]=> string(3) “401” [“wowzaServer”]=> string(8) “4.8.19+4” [“success”]=> bool(false)
REST API works only without authentication (none).
Any suggestion to bring back authentication?
Thanks.