"Invalid Credentials (Failure)"

Who is the email account provider for this email account?

Did this occur at home when connected to a wi-fi network you have at home, or when connected via EDGE?

Are you also accessing this email account with an email client on your computer and if so, are you able to access the account with the email client used on your computer for accessing the account?

Is this account a POP or IMAP account?

If an IMAP account, you can delete and recreate the account and no messages will be lost. If a POP account and you delete and recreate the account, any messages no longer available at the incoming mail server for the account will be lost, along with all messages sent with the iPhone.

Have you tried deleting and recreating the account on your iPhone?

A Gmail account can be accessed as an IMAP or POP account.

Did you use the Gmail account preset when creating the account on your iPhone?

If so, the account was created as an IMAP account on your iPhone, and the available IMAP Path Prefix also indicates this.

EDGE is at&t's data or internet network - which is accessed via at&t cellular network with the iPhone. The iPhone can connect via an available wi-fi network (which is much faster access), or via at&t's EDGE network, which is much slower than wi-fi. If you have access to an available wi-fi network, I recommend using it. The iPhone will switch automatically between an available wi-fi network you have previously accessed with your iPhone, and at&t's EDGE network.

I would try deleting and manually creating the account on your iPhone. Using the Gmail account preset when doing so automatically creates the account as an IMAP account, and no messages will be lost since all remain on the server - including sent messages.

The same exact problem started last night on my phone. I have to use a gmail account strictly to allow my iphone to have e-mail access. My regular e-mail goes through at&t and after dozens of trips to the apple and at&t stores to try and get the phone to work, we created my current gmail account to catch forwarded mail from at&t. I have reset everything this morning using both imap and pop and am still receiving the error message. This has to be a gmail problem.

This is a CAPTCHA problem...
Try the following address :
https://www.google.com/accounts/UnlockCaptcha?

Don't be afraid it will tell you that your account has been deactivated... just go ahead, you will not loose any email.

Message was edited by: bouem01

After several attempts to sign in to gmail via the google website, I was able to log in. Once that happened, whatever was locking up the account has seemed to go away. At this moment, my iphone is back in the e-mail business.
Thanks to all that offered suggestions.

Try shutting off the wifi and use the EDGE network.
I was getting the "Invalid Credentials (Failure)" message when trying to create my Gmail account settings on my iPhone while connected to the wireless portal on my home network. After about an hour of frustration I finally turned off the WiFi on the iphone which defaulted me back to the EDGE network ... and Gmail worked perfectly. When I turned the Wifi back on again, the error message came back as well, so there is still a problem somewhere ... I suspect my AT&T / Yahoo internet service.

This is also happening to me on my iPhone and it started last night as well (Fri. May 30). For the record, I'm using IMAP gmail and I'm getting the Invalid Credentials error message. It seems to only be a problem over EDGE.

On my laptop gmail is working in Mail as per usual, although there was a moment this morning when all of my emails from the last week were suddenly duplicated in my inbox, although the duplicate emails disappeared after twenty minutes.

bouem01 wrote:
This is a CAPTCHA problem...
Try the following address :
https://www.google.com/accounts/UnlockCaptcha?

This alone didn't fix my issues but doing this and then also changing my password seems to have fixed it.

I had this same problem using Mail on my laptop, it just popped up spontaneously. I saw someone else recommend changing the servers from imap.gmail.com and smtp.gmail.com to imap.googlemail.com and smtp.googlemail.com. I changed them and it worked right away. FWIW, I have a different gmail account that still works on the old servers. Not sure why. Hope this helps.

OK. Same problem. After reading the discussion and trying the appropriate fixes, I'm still not getting my Gmail account to work on my phone if I'm on Wi-fi or Edge. I tried creating a new account, but that doesn't work and once I did, I no longer see the area on the outgoing settings that allows me to change the smtp settings to try the imap.googlemail.com thingy. My Gmail box works fine on my Macbook though and I can get into Googlemail through Safari on my phone. Very frustrated. If anyone can help there is a gold star involved from me to you.

My laptop was stolen, but I have another G3 that needs to be updated. Where can I send this for repair.
Thanks, -M
P.S. I'm dirt poor