I am trying to sign in to UMLS Terminology Services (UTS) to download files, use VSAC, or use the UMLS Metathesaurus Browser, and I am getting an error. 

If you have a UMLS license / account, try clearing your browser cache and cookies or use a different web browser and try signing in again. If you continue to get an error message, please write to the NLM Help Desk and provide the URL where you are receiving the error as well as a screenshot of the error. 

If you do not have a UMLS license / account, you will need to sign up for one here: https://uts.nlm.nih.gov/uts/signup-login. NLM will review your request within 3 business days. Once your request is approved, you will be able to access resources that require a UMLS license.