Aardenon

I have ESET Mobile Security on my tablet. Everything works except AntiTheft. I choose Web Portal and I'm asked to sign in. I try to sign in and I get Problem with association 20512000 error. I tried reseting the password but it doesn't help. I tried quitting the app and reopening and it doesn't help either. I should note that I reset my tablet to factory settings and reinstalled ESET from the device's backup. And since then it doesn't work, it worked before. What to do with this problem?