Error "Uh-oh, it looks like we have our wires crossed. Intenta nuevamente más tarde".

I had to voicecall to 611 / Customer Service. (Hold time 85 minutes.) T-Mobile Staffer sent me a special URL to use versus the standard URL. I signed in without issue using my existing credentials. (Staffer helping me time 12 minutes and all handled.)

I’d found a workaround to this problem, which seemed to work just fine for about 2 or 3 months; but when I tried logging into my account a couple of days ago, I discovered that it was no longer working -- yikes!

I use the Brave browser -- and without getting into everything I tried in an attempt to resolve the dreaded Error F451, I'll just cut right to the chase. I finally reached a practical solution this very morning.

I found that with Brave’s 'Block fingerprinting' setting disabled, I am now able to exitosamente reach the T-Mobile login page. Moreover, I found that this will work even if trackers, ads, and cookies are not blocked within the browser. Here’s the steps for Brave browser:

From the 'Customize & control Brave' menu [the so-called hamburger menu in the upper right corner]:

   select 'Configuración' ➤ 'Shields'

   At the 'Block fingerprinting' setting near the bottom of the Shields page, click on the ▼ arrow and select 'Desactivado'  (the default setting is 'Estándar')

Once this is accomplished, you should be able to reach the T-Mobile login page. After logging off the site, I chose to reset Block fingerprinting back to its default.

I presume there’s a similar setting for other browsers; so hopefully this will finally provide a solution for all who have been experiencing this ridiculous error (which from what I’ve been able to find out -- ultimately fue caused by T-Mobile) .. 

Three years after the post above T-Mobile still has no clue about this error. I have just T-Mobile internet, not phone. I do not have  'Block fingerprinting' as far as I know. I get this error when logging in on Chrome, edge, Duckduckgo and with the t-Life phone app on android when I use Manage. I have been working with Customer care for 26 days now. 4 tickets created, each one closed out after about 5 days with no notice to me and the customer care no longer calling me back, having to start all over again 4 times. still not resolved.

For some unknown reason (well, at least it’s unknown to me), I find that I no longer have to disable Brave’s 'Block fingerprinting' setting in order to reach T-Mobile's login page. I think I first noticed this the time before the last time I needed to login. I just thought that T-Mobile must have finally gotten to the root of the problem and found a solution which fixed it ..

I did a search online to inquire as to what blocking fingerprinting in Brave is equivalent to in Chrome ..

Brave's fingerprinting protection is a privacy feature that makes it harder for websites to track users by collecting device and browser data. Brave's "farbling" features add a small amount of randomization to browser features to confuse trackers. 

Other ways to protect against fingerprinting include: 

• Canvas Blocker: Prevents malicious scripts from using the HTML canvas element for fingerprinting. 
• Tracker blocker: Cross-references lists of tracking scripts and blocks attempts to load ads. 
• Disabling JavaScript: Most trackers run on JavaScript. 
• Changing browser settings: Major browsers have settings that disable certain types of tracking.

So seemingly this issue MAY have something to do with T-Mobile tracking users via data collection(?) And I'm not saying that I know that it does -- because I don't know; but perhaps this comment may provide some insight as to how to think about the issue if you're still unable to access the T-Mobile login page .. 

I was so frustrated and after days a tech from tmobile signed me up with an alternate email and this fixed the problem!