Teachme Biz does not support specific functions such as device certificates set up on the other service (IdP) side.
Please check with the IdP side whether you can integrate with the SP-side app (Teachme Biz) without using device certificates or client certificates.
If you are using HENNGE One as the IdP, there may be a workaround using 'HENNGE Lock'.
Please refer to the linked information for details.
Related: HENNGE Lock (Japanese external site)
https://hennge.com/jp/service/lock/
※Please contact the provider for any questions about HENNGE Lock.
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Related: Which services (IdP) can you connect to for single sign-on (SSO)?
https://help.teachme.jp/hc/en-us/articles/900006441703