Very odd. Should be pretty much plug and play as you've seen before. The LED blink on power up shows that the Modulo is resetting, so it SHOULD be trying to come online.
We can check the Modulo pretty quick if you want to try a quick test. The Modulo USB port also presents a serial port to your PC. Grab your favorite serial terminal program, if you have one, and let's connect it to the Modulo.
For the Mac, I use a terminal called "minicom" which is installable via homebrew. Also available on Linux. For any Unix OS (Mac included) you can also use the "screen" utility that' already installed as well.
The Modulo serial port will look like /dev/tty.usbserial-XXXXXXXX where the Xs are a reasonably-unique alphanumeric string. You can verify you have the right port if "ls /dev/tty.usbserial*" shows the port go away when the modulo is unplugged and come back when it's plugged in. The serial port on the Modulo is 38400 baud.
If you use "screen" you can connect to the serial port with "screen /dev/tty.usbserial-XXXXXXXX 38400" and pressing enter.
When you're connected, get a wire jumper or paperclip or something and short pads 2 and 4 on the exposed pads next to the ASR-1 (pad 1 is the one with a square around it, so short, briefly, the pad next to the square pad and then the last pad in the row. The LED will blink again when you hit those pins, which resets the ASR-1. You will also see on the serial port output a copyright notice come out of the ASR-1 and the device's association ID. This ensures that the ASR-1 not only resets but actually finishes booting and comes ready.
Though to be quite honest, that's almost assuredly /not/ your problem. Interesting info to know, and good to do to be sure, but what we see the vast majority of the time is issues with the BT stack on your mobile. You can try the easy things like toggling BT off and on, or rebooting your phone, but if you can let us know what kind of device you have and waht OS, I'll dig around with the app guys to see if there are any connectivity issues we've seen with your type of device.