ContributionsMost RecentMost LikesSolutionsRe: Delivery Failure code 535 - authentication reject using gmail to import from cox I've been there, done that. All setting are as specified in this link and have been that way for some time. The question is why does authentication work OK one minute and not the next. Re: Delivery Failure code 535 - authentication reject using gmail to import from cox ColleemD, Outgoing Port 465 with SSL enabled. The authenication failure seems to be coming from Cox Delivery Failure code 535 - authentication reject using gmail to import from cox Have been getting this occasionally the past week or so. If I wait a few minutes and send the same thing it will usually go through. All settings for Cox servers including password seem to be correct. All gmail settings appear to be correct and everything works MOST of the time. Any ideas? Solved