Hi @NgariNdungu and welcome to the community.
If my memory serves me right, a basic auth can also be written as
Basic base64Encode(username:password)
So if you have a username: [email protected] and a password: password, your base64 encoded value should be
Authorization: Basic am9obi5kb2VAdHlrLmlvOnBhc3N3b3Jk
Let us know if that works.