verification failed this action cannot be completed

I have had this issue for several days now myself. It started with my iPhone 6s and now on iTunes as well. After digging through old support posts I found a solution that actually worked. I don't know if it will work for everyone but it did for me and hopefully it will for you guys too.

[POSSIBLE] SOLUTION:

1) Log into appleid.apple.com* (I had to log in on my phone browser as the login page is broken on Chrome on PC [at least for me]).

2) Go into the security section and scroll down to "Two-Factor Authentication" and turn it off/disable it.

3) Follow any prompts (it made me create new security questions) and then wait a minute to make sure the change registers.

4) Try logging back in on your devices.

*If you aren't able to log in to the site, your account may be blocked. There are other posts explaining how to fix that.

Hope this helps.

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This issue has been happening for at least four days. The work-around I’ve found is to attempt to log in 10 to 15 times in a row and eventually it will work. Annoying, but it’s better than not being able to use Find My IPhone. Seems like Apple has some sort of authentication issue the are likely working on to fix ASAP. Hope this helps.

This is happening to me as well. I've called Apple support and they were unable to fix it. I have tried updating my phone, resetting my settings, and resetting my network settings. I have also changed my password. Nothing has worked.

I'm having the same problem. It seems to be connected to two factor authentication. As long as its not enabled, I'm able to log in using the Apple ID password. The second I try to enable two factor authentication the message "This action cannot be Completed" comes up when I try to log in to anything connected to my AppleID (iTunes, iBooks, iCloud etc.).

Btw, I've tried to turn off/on my devices, I've removed them from my AppleID web page and logged back in, I've re-formatted my iMac and my MacBook.

The only thing that works is turning off two factor authentication.

It seems that any login that is effected by the two factor authentication (even though its not possible to authenticate that way, e.g. iTunes or Apple account from iOS settings) is blocked by the two factor.

Fix it, Apple. Not at all something I'm expecting from you.

Try restarting the device -- Restart your iPhone, iPad, or iPod touch - Apple Support.

Do you have access to another network where you can try to log in?

Try a forced restart.

Reset Device

Reset – iPhone 7

Hard reset

same here, its been annoying me for days on 4 devices....done the attempted log ins and after about the 8th try it works

Great hint. Thank you. It worked on my iPad just turning on two factor authentication in the Settings of my iPad . Did not have to go to the Apple ID website.