The release which took place on Monday 8 January introduced a slight change in the provision of the access token. This change may cause issues to users who coded the handling of the access token too restrictively.
The access token tag now lacks one whitespace “ “.
OLD - Before 8/1/2018 (one whitespace before colon):
"access_token" : "
NEW - After 8/1/2018 (no whitespace before colon):
As a consequence, the starting character of the token may not be parsed correctly resulting into a 403 error message “ The request has been rejected due to the Fair Use policy”.
If you encounter an issue of this kind you should make sure that the parsing of the token is independent of the presence or not of whitespaces.