had this same issue,though everything was correct,i went into my gmail setting,thats my personal email settings and changed less secure app from off to on, then i retried my cctv email function on floureon,test email and it worked..
what i dont understand is after getting email notification in my inbox i deleted them and i realise i stopped getting email alert .i went into the dvr and test sent email. says wrong username or password, checked to see if less secure app in gmail was off.it wasnt. have no idea what happened. still battling this issue