Not that "user agent" couldn't mean something else - but Soundmondo is a web based tool and "user agent" in the web context is the string your browser sends to identify itself. It tells the website your chrome version, your operating system details, etc.

Some people change their user agent since it helps certain websites display. Or install a plugin that alters the user agent. A popular legitimate use of this would be a cell phone which normally advertises it wants a mobile site - and someone wants to see the desktop version of the site - so they have the browser spoof a desktop version of the user agent (the Dolphin browser does this).

When you first start using a WebMIDI site on Chrome - the browser asks if you want to grant the website full control of your MIDI device. This is required for any WebMIDI site (like SoundMondo) that requires use of SysEx.

Sticking with a pure web-world set of theories of what's going on here - beyond granting permission to the site on your browser to use Sysex - you cannot use SysEx (even with permission) if the user is connected through a non-secure channel. Your soundmondo connection needs to have the "https://" protocol. Not "http://" and not empty - if the browsers even leave off the protocol anymore. So check to see you are connected to soundmondo using https://

The site is supposed to redirect you (or well behaving sites should do this) if you are connected through http:// and not https://. That's why most users don't need to pay attention to this. The site will pull the carpet out and replace it with a secure one. That said - I have seen (and complained about) this site not always redirecting unsecured connections to https://. So if this site is any indication - then it's possible something is failing with this redirection on soundmondo for you. I believe you could also have some browser settings that would prevent this redirection from happening because it generally needs no user intervention -- and browsers keep changing the rules on what does and what does not need a human to approve or know is happening.

That's all I have for now.

Hi,
I have the same issue, the protocol is https, installed Yamaha Steinberg USB Driver, Chrome 78.0.3904.108, Windows 7 Professional.

Is there another solution? Thanks

Wish your screenshot wasn't as cropped in order to see the top line to see if MIDI devices are allowed.

When you first navigate, you should see:

Allow, then should see:

Ignore the "Disconnected" -- I don't have my keyboard plugged in at the moment.

Note that in the first picture if I press "Block" instead of "Allow", then I will see:

Hi Jason,
thanks a lot, I followed your instructions and now works!!!!! 🙂 🙂 🙂 😉 😉 😉 😉

Jason, thanks for your help in this thread.
I'm a newbie (to the CP88 and Soundmondo) and although I *think* and believe I've set everything up correctly, I am having no luck connecting the CP88 to Soundmondo. I see only the SecurityError: message. I'm hoping you might be able to offer some suggestions - although, I am on a mac, and I think your screenshots are Windows-based. Thought it worth asking nonetheless.
I began by installing the Yamaha Steinberg USB driver (v2.0.2.) There's a note in the driver installation instructions about needing to allow some 'permission' on the MacOS during install - which all went exactly according to plan. The install completed, and the computer rebooted as anticipated. When I open Utilities>Audio Midi Setup after the restart (and after connecting the CP88) the CP88 is not listed. So I'm guessing that this is the root of my problem!? But - I'm pretty sure I've followed the driver installation instructions to the letter, and the CP88 manual's instructions too - as per the Notice on p27 I'm not using a USB3.0 cable, although I don't know what an 'AB type USB cable' is -- is this something magical?

Your screenshots raised another question for me though; you say to 'Ignore the "Disconnected" - I don't have my keyboard plugged in at the moment.' So this implies that the browser's invitation to Allow (or Block) access to your MIDI devices does not appear only when the device is connected, nor only when you're signed in - because neither is true in your screenshot? If this is so - why might I never have seen that invitation to Allow?! I'm using Chrome Version 78.0.3904.108, not incognito or anything weird in terms of connection. I've also checked I'm connecting to https://soundmo...
When I arrive on the site, before (or after) signing in and (failing to) connect the CP88 I only see the same error message which Scott and Marco posted about.
I've spent hours messing with this and gone precisely nowhere. I've searched the net for help and advice, but your post in this thread is the best advice I've found! So, thanks again - and here's hoping you might be able to see where I'm going wrong. Cheers.

Please ignore my plea above - I'm sorted! I found that a different usb cable connected the CP88 to the computer - and then that Chrome had automatically Blocked the device control, I was able to intervene manually to Allow. All connected - now need to learn how to use it :p

Ignoring the plea - but this may help someone else.

An AB type USB cable is a USB 2.0 cable that is also commonly referred to as a "printer cable". Since it was a bad habit of printers NOT to ship with the required cable and 95% of the use of this style of cable was for printers. One end has a rectangle that plugs into traditional USB ports (not type C - the larger rectangle we've seen for a while) and the other end - that plugs into the keyboard - is more of a square shape.

Type B connector is on the left. Type A connector is on the right.