Error Authenticating

Hello, my client changed their gmail password recently which seems to have kicked them out the api connection. I have been attempting to reconnect but it keeps sending us back to the original error which reads:

Email Source: Wordfence Security
Mailer: Google / Gmail
{
"error": {
"code": 401,
"message": "Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.",
"errors": [
{
"message": "Login Required.",
"domain": "global",
"reason": "required",
"location": "Authorization",
"locationType": "header"
}
],
"status": "UNAUTHENTICATED",
"details": [
{
"@type": "type.googleapis.com/google.rpc.ErrorInfo",
"reason": "CREDENTIALS_MISSING",
"domain": "googleapis.com",
"metadata": {
"service": "gmail.googleapis.com",
"method": "caribou.api.proto.MailboxService.SendMessage"
}
}
]
}
}

I noticed it mentioned WordFence so I deactivated the plugin. Still get the error. I also reset out secret key. Still get the error.

Please help!