Cannot Login to connect.garmin.com

Having the same issue on multiple computers and multiple networks. Tried different browsers and clearing cache. No effect. :(

I have spent the last three days going back and forth with Garmin Support - they have no clue what is causing this. We've covered the basics, clear the browsing data, clear the cache, clear cookies to no avail. I've changed my DNS servers (that worked for a moment but then it didn't. In the end, they suggested I reset my router and contact my ISP. Folks - this is not an ISP issue. This blank page your browser displays is being generated by Garmin's own servers and is typically associated with a Content Management System error - but no one seems to get this or want to escalate it to the code cutters who might have a solution. The only work around that works is to login via forums.garmin.com (remember me!) then open Garmin Connect and you will be logged in. The error is CLEARLY in the login script for Garmin Connect. One support person suggested the error can associated with an bad character in the user name....but the script does not send the user name until it is entered - so that makes no sense. Bottom line, the problem is at their end but they seem unwilling to acknowledge this.

I have not been able to log in for several days with the same issue. Tried Chrome, IE, and Firefox. I deleted all Garmin cookies, and I am logged in to this forum, still get the 'disallowed key characters" message.

I have a device with an Ant, so I can't even extract the file to upload to a different site.

Any suggestions would be very welcome. Thanks.

Bottom line, the problem is at their end but they seem unwilling to acknowledge this.

Oh well... I guess we'll have to wait for a long time until someone at Garmin escalates this or when none of their login script work anymore.

For now, at my work it's working fine with Win 8 and firefox/ie.
At home with win 10 and firefox/ie/chrome/edge it's not working at all.

My workaround is to go to Garmin Express and then launch the connect from there.

Same Issue here...started today...I finally got my app on the phone to sync at least but Garmin Connect won't let me in...I've cleared the history and I either get "disallowed key characters" or now a blank screen that is new...if it's multiple people it's not something I'm doing...and this has never happened before.

oh the workaround didn't work...even through Garmin Express I cannot log in, brings me to the same blank screen

It was down for a short time this afternoon. It's OK for me now.

I just fired off an email to support through their website, but I thought I would post this here in case others are having the same issue. When I click on 'sign in' on the garmin connect website I get a nearly blank page that says only: 'Disallowed Key Characters.'

Is anyone else having this issue?

Same problem with me. I get the message "Disallowed Key Characters" in three browsers, my Ipad and my Samsung phone....

To add to this long and discouraging list, same problem here: login to https://connect.garmin.com/en-US/signin results in error message "Disallowed Key Characters". Can't get any browser or version to work. Very annoying. Tried Firefox 54.0.1 (Mac), Opera 12.16 (Mac), Vivaldi 1.10, Safari 10.1.2, Chrome 59.0 (Mac). No more luck in iOS.

I find it utterly unacceptable that no one from Garmin support has posted to this queue.

Wrote to Garmin Twitter. Waiting to see if I'll get a reply.

Finally found a workaround by connecting via Garmin Express and pasting the link in Firefox.

Seems like Garmin fixed the issue. It's working fine for me now.