Invalid Authorization error in API

I am getting below error when calling API ‘https://api.company-information.service.gov.uk/company/01234567/persons-with-significant-control

{
“error”: “Invalid Authorization”,
“type”: “ch:service”
}

I have passed api key in ‘Authorization’ key as 'Bearer ’ + [API Key]
I have also tried to do base 64 encoding then passed api key and also tried by selecting basic authentication and provided username and password still getting same error.

Is that the streaming API and did you remember to place the colon before base64 encoding?
Refer to the documentation (Using basic Authentication towards the bottom) Streaming API: (company-information.service.gov.uk)