I am trying to arm my system remotely using the app and it appears to be timing out. I tried logging on to the suretydiy alarm.com portal and sending the arm command and it failed as well.
Things to check:
Are signals coming from your panel to ADC working fine? Is it just incoming commands not functioning or signals in both directions?
Have you added a Cell network booster at your location? This can interfere.
I would suggest first running a manual cell test. If all of your commands go through shortly after that, it narrows down the issue.
If signals out are not working, it is likely a local problem with equipment.