Worst case, contact the mfgr. I suspect you have been receiving emails from them with instructions such as what @volvobuff provided. The last couple emails (12/9) I received while my unit was in transit prior to delivery earlier this week had the detailed instructions you need to follow and essentially said if all else fails, you can return the unit, they will send you one that has the current level of more easily updated firmware, or you can request a refund. I followed those instructions to the letter and while it was a little wonky (translation issues, I suspect), I had no significant problems doing the update of the adapter first in my home with a USB stick and direct-to-110V USB charger, then the initial connection in the cockpit to my new XC60 in the garage — didn’t have the “...Connecting” problem you are encountering (that email I reference says it was happening on Honda/Jeep, and to go through the install process to the letter again), so perhaps something has happened to your unit when you were doing some of the steps outside the car...I had my iPhone forget my home network and confirmed that I was connected ONLY to 4G LTE and tried to connect again. It still gets to the Connecting... message and no further. I also tried updating the firmware using the link you provided (thanks for the instructions and url) but never had both red and blue LEDs lit, waited for 10 minutes to be sure. Any other ideas?
If I were you, I’d try the steps 100% to the letter again as outlined in the instructions provided, and if that fails, contact the mfgr to get your unit returned and a new one sent so you know where you are in the process. Good luck.