Admin Email links

After the client books an appointment, the admin receive an email to confirm or cancel the appointment. The confirmation link at the bottom generates an error viz:

Forbidden
You don’t have permission to access this resource.

The link is as follows (url disguised) :

https://url.com/wp-json/wp-mail-smtp/v1/e/ZGF0YSU1QmVtYWlsX2xvZ19pZCU1RD0xNDAmZGF0YSU1QmV2ZW50X3R5cGUlNUQ9Y2xpY2stbGluayZkYXRhJTVCb2JqZWN0X2lkJTVEPTI3JmRhdGElNUJ1cmwlNUQ9aHR0cHMlMjUzQSUyNTJGJTI1MkZwb255cm9hZGF1dG9zcGVjaWFsaXN0cy5jb20lMjUzRl9lYS1hY3Rpb24lMjUzRGNvbmZpcm0lMjUyNl9lYS1hcHAlMjUzRDE0MiUyNTI2X2VhLXQlMjUzRGY3MWI2NDEwMTc0MTAyY2ViNmY3YTc5MDQ3M2EwODUyJmhhc2g9NDBhOGE1MGYwNmQyNmY5NDY3MDllODFjNWMyNTRkN2ZmOTgyOGJhMDM2ZDMzZDc3MzQwMmZkNjJiNjc1MjQwMw==

Is there a way to include other links on the Email that the Admin receives?

Regards

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