Exchange 2016 OWA - reCAPTCHA

New Contributor

I'm trying to implement reCAPTCHA on my Exchange 2016 OWA and ECP login page.


I followed this guide but I'm still unable to get this to work:


When I go to the login page using the DNS name (So using the domain I entered in reCAPTCHA) nothing shows up and I can login with just my username and password with no extra checks.


When I go the the IP address I get the error "ERROR for site owner:Invalid domain for site key" which is normal but it shows that the reCAPTCHA is there.


Has anybody else ever implement reCAPTCHA and give me some pointers or guides how they did it?

5 Replies
Hello Shotterke,

I think you are trying to implement ReCAPTCHA because of security reasons?

Wouldn't it be better to use Azure Application Proxy so you can use things like Conditional Access?
I'm referring to a article created by Mike Parker:

You can then even use SSO with Windows Authentication to have only one sign-in experience from the Microsoft Azure sign-in page.
best response confirmed by Shotterke (New Contributor)

Hi PvB91,


We aren't using Azure so that won't work.


I did some more testing during the weekend and decided to start from scratch and also reboot our mail servers. After that everything was working like it should.



Hi @Shotterke 


Please follow these to get reCAPTCHA key first, and make sure your FQDN for OWA has input to Google reCAPTCHA admin console


And it will be great to use reCAPTCHA v3 for Exchange OWA by following this comment

@Aska Su 

Unfortunately, page on GitHub give s Error 404 and is not alive.

Have some info from other place or may be from your experience for using Google ReCaptcha v.3 on Exchange OWA 2013/2016/2019?

Tried to use it but it's not working. Only recaptcha v.2 is working OK...