If you cannot log in to the environment where your accounts are linked, there is a possibility that you did not access it in a correct way, or your account does not exist anymore (either your account is suspended or deleted).

If your accounts are linked, you need to log in from the login page of kintone you are licensed by using your guest account.
Once your accounts are linked, you can no longer log in from the guest user login screen using your guest account e-mail address and password. You also cannot disable the Link Account feature you configured.

In the following section, we describe how to solve the issue.
As a first step, try the solution described in Try to Log in with the kintone Account. If you still have a log in issue, check that your account is not suspended or deleted, then try the solution described in Ask to Get Invited as a Guest Again.

On the login page for guest users, click Login Using kintone Account.

Enter a subdomain of kintone, which you are using in your company.

If you cannot log in even after specifying the subdomain, one of the possible reasons is that your user account does not exist (either your account is suspended or deleted) in kintone in your company.
Contact the administrator of kintone you are using to check whether your user account is not suspended or deleted.
If you cannot log in due to account deletion or suspension, you need to get invited again as a guest user.

Before you ask your guest space administrator to invite you again, a kintone Administrator needs to access kintone Administration in the kintone environment you are using and then delete your account in the "Guest Management" settings.
Deleting guest users

After that, you need to ask the guest space administrator to invite you as a guest user again.
Guest Management (Inviting Guests)

If you want to use a different e-mail address to get invited again, your original guest account does not need to be deleted.