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I have this problem - Outlook 2016 doesn't accept password or app password - and i think it is a growing World wide Microsoft problem :-(
See also here: https://www.reddit.com/r/Outlook/comments/19dx64p/outlook_2013_windows_10_suddenly_not_accepting/Outlook gives me this: (startede yesterday)
I have 2 PC's with HOTMAIL accounts in Outlook 2016 ...
They both have this error.
I do get mails ... but I can´t send mails. Yesterday it did work for 1-2 hours ... but right now the error is there all the time :-(
Please help me.
Thanks in advance
Pierre
Using classic Outlook for Windows in business environments
Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.
Again, the inconsistent nature of this problem continues. One account this morning had no issues, the other did not receive any email overnight. The above explanation as to which server, DNS, IP address, etc is being used/called, adds much color to this ongoing issue and most likely explains my experience. Nonetheless, what a royal PITA!
T-Mobile uses IPv6 which is a whole other set of IPs, though when I switched to mobile data (I have Tmo also) it worked just now.
If I do go back to the "credentials needed" tomorrow I'm going to try one of the IPs I have as working along with the accept any certificate just to see if it works. My phone isn't rooted so I can't edit the hosts file (that's really something that should be in developer options).
I can also add a DNS host entry to my router but that will only work at home on wifi.
I'm curious what workaround 9Folders did and if it was potentially something like this.
That step didn't work for me anyway. I suspect that person just got lucky timing wise and it was coincidence.
- Here seems to be the important part - go to your impacted email account online via Outlook Web. Go to Settings then search for "mobile", it should take you to a setting page and your logged in Mobile devices are listed.
I have no "mobile" option in my Outlook.com settings.
It makes sense. My failure rate on T-Mobile network was nearly 100%. I have T-Mo for phone and home internet. At my work with Comcast, it was much lower. I suspect the load balancing probably has region and internet backbone related decision factors.