I have to say if I read this correctly, this is wrong on several levels. I don't know where you are, but you should never install or tolerate the installation of EM locks in a manner that users have to break the glass to get out. This violates the Life Safety Code 101 in its entirety not to mention common sense. You should install a mechanical means of egress (usually a big green button) adjacent to the door that is tied directly to lock power. Pushing the button interrupts the power if the controller fails. You absolutely must provide a means for escape.
With the other poster, if you have an EM lock that can be removed that easily from the outside, that is another total failure on someone's part.
Second, you should seriously consider replacing or repairing that controller. It is either bad or is a POS.
Lastly, we use a WEB Relay tied to lock power as a backup. Never had to use it, but we test it annually and it works like a snap. We can open the door with any mobile device that has the app or a desktop, from hundreds of mile away. Only two people have access to it. As long as you have internet access at the facility, it works.