I assume it is OAuth2 token. Yes you can use it with Mail.dll,
remember however that token must be issued for
GoogleScope.ImapAndSmtp.Name and GoogleScope.EmailScope.Name scopes.
GoogleApi api = new GoogleApi(accessToken);
string user = api.GetEmailPlus();
using (Imap imap = new Imap())
{
imap.ConnectSSL("imap.gmail.com");
imap.LoginOAUTH2(user, accessToken);
imap.SelectInbox();
List<long> uids = imap.Search(Flag.Unseen);
foreach (long uid in uids)
{
var eml = imap.GetMessageByUID(uid);
IMail email = new MailBuilder().CreateFromEml(eml);
Console.WriteLine(email.Subject);
}
imap.Close();
}
You can find more here:
https://www.limilabs.com/mail/samples#imap-gmail-oauth2