I installed Remote.it about a year ago and I had it working. I didn’t use it for a while but when I tried it again later, it is not longer connecting to the Synology NAS.
I followed the instructions and I checked again and again, some 25 times, on my Windows 10 PC and on the Synology NAS. Everything is seems OK.
I deleted everything and reinstalled. I set up the connection as HTTPS. Remote.it shows it is connected to the NAS, but when I click on launch it, it goes to the browser and it times out: “An error occurred”.
It is hard to say the error. I would suggest trying to debug it in a similar fashion as described in this post:
You can check that you can get to the Synology NAS while on the LAN. If you installed remote.it on your Synology NAS and you got an update there might be an issue with the Remote.It install. If you used another computer as a Jumpbox then check that the LAN address for your Synology NAS has not changed.