Alertmanager Notify attempt failed, will retry later username and password not accepted

i have installed prometheus in that i also install alertmanager for email notification into my gmail account

below is the error im getting i have given app password but still im getting error

level=warn ts=2020-09-30T13:25:50.041Z caller=notify.go:674 component=dispatcher receiver=slack integration=email[0] msg=“Notify attempt failed, will retry later” attempts=3 err="*email.loginAuth auth: 535 5.7.8 Username and Password not accepted. Learn more at\n5.7.8 m1sm194703lfr.32 - gsmtp"