In order for your Copier/MFD (Multi-Function Device) to scan to email, it needs to be set up with an email account to send out your scan. Gmail accounts have been widely used for this purpose. Originally when many of these accounts were set up in the MFD, the email address and Gmail account password were entered into the MFD.
Starting on May 30, 2022, Gmail will no longer allow the account password to be used by the MFD. If your device is set up this way, scan to email will start failing on or after May 30th. A security upgrade to your Gmail account will be required to continue using Gmail for your scanning.
This upgrade requires an App Password to be created. This is a special password that allows the copier to send out your scan to e-mail but is not used to access your Gmail account directly. This provides enhanced security. More info on this can be found at the following URL: https://support.google.com/accounts/answer/6010255
Unfortunately, there is no easy way to tell if you are using the upgraded method of scanning to your Gmail account.