You can check referrer information by accessing the "Teachme Biz Usage Environment Diagnosis Page" from a web browser or mobile browser.
If the referrer (referrer URL) restriction feature is not working as intended, please refer to the link below to check the referrer information.
Related: Check Referrer Information (Web Browser Version)
https://teachme.jp/8/manuals/42393733
If referrer information is displayed
Please allow the domain of the URL displayed on the diagnosis page (e.g., https://example.com) as the referrer URL.
※ Referrer URLs are evaluated by domain.
For how to register, please check "What is the referrer (Referrer URL) restriction?" here.
Related: Restrict access with a specific referrer URL or password (Web Browser)
https://teachme.jp/8/manuals/10033436/
If referrer information is not displayed
Referrer information may not be retained depending on the environment of the page that is permitted as a referrer URL.
If referrer information cannot be confirmed, the referrer (Referrer URL) restriction feature cannot be used.
Please consider one of the following measures.
Modify the source page to send referrer information
Implementing a "meta referrer" tag, which allows you to specify referrer transmission when navigating to a page by clicking a link, may resolve the issue.
For tag implementation, please check with the environment provider of the page permitted as the referrer URL.
Apply access restrictions other than referrer restriction
Folders released outside can also restrict access with a "Password" in addition to a referrer.
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Related: What is the referrer (Referrer URL) restriction?
What is the referrer (Referrer URL) restriction?