Back in August 2020 I blogged about why Crossref was decommissioning the TDM Click Through service, whilst continuing to collect member-supplied TDM licensing information in metadata for individual works. Only two members had loaded licenses to the service.
Elsevier already provided an interface for researchers to register for an API key.
Wiley has now provided its own service too.
Researchers should switch to using these services from now on. Crossref will decommission its TDM Clickthrough service by the end of February 2021.