Why do I keep getting SIGN-IN FAILED. SERVER PW HAS CHANGED. ENTER NEW PW on my cell phone?

I had the same issue since my Samsung Galaxy S3 did a software upgrade about a week ago. Here's what finally worked for me after deleting stored passwords, trying to put the password in under incoming mail settings, and all the other nonsense that people said to try. Go on the computer and change your Yahoo password (just do something easy like a capital letter). Then go to Playstore and uninstall all Yahoo apps (mail, messenger, plug-in). Do a full shut down on your phone, not a restart, for a few minutes. Turn your phone on and when it is done rebooting, go back to the playstore and reinstall your Yahoo apps (all 3). Then go into your mail settings and go to the incoming mail settings and put in your new password (on your phone, not the computer). Good luck! This worked for me

I had this same problem. I went to my yahoo mail and went into settings. From there it will let you choose which system you are working off of and give you a 16 digit code to punch in the password field on the failed password notification that keeps popping up. So you don't have to delete anything or reset passwords. It was a simple fix. Finding it was what took a while. You will need to be on a computer to do this. Hope this helps.

Server Password

it looks like I am not the only one to have this problem...I really believed some one was trying to hack into my yahoo mail account...yahoo tech support is sloooow. My Samsung 3 did update a number of days ago and I did change my password 3 times today because I had received a bogus email today 11/28/2015 asking me to update my email storage...sooo like a dummy I typed in my password. when I realized what a mistake that was I contacted email support after changing my password 3 times. I still do not understand why the above message only shows up on my mobile device and not my desk top..... where is yahoo tech support when you need them. Better yet i need to look at all my in coming mail a lot closer

Sign In Failed

I was able to solve this issue on my phone. I changed my pw on the Yahoo website. And then I manually retyped it into my Mail App incoming mail settings. It worked. I didn't have to DL the Yahoo Mail App and add more apps to my phone.

I also had that problem. Other people's answers didn't help. Go into your settings, accounts, mail. Delete your yahoo account. Then add the email account. Go into manual setup. Don't change settings but fill it out. This works but the only problem is your inbox will be combined with your spam folder.

Go to your Yahoo account security settings at the bottom slide the bar to Allow apps that use less secure sign in

"Some non-Yahoo apps and devices use less secure sign-in technology, which could leave your account vulnerable. You can turn off access (which we recommend) or choose to use them despite the risks."

I think it's a design flaw on the part of Yahoo, forcing you to relax security standard in order to use internet enable devices to access your emails. But it worked.

Ive had the same problem for 2 days and finally sorted it , typed in my original password and ticked box to show password and that worked

Hope this helps

Luckily I only had to turn my phone off and on again to rectify the problem. Pleased that I wasn't the only one with a sign in failure. Again, my phone is a Samsung Galaxy 3. Does anyone know why this can happen. Many thanks.