I cannot sign in Adobe Digital Edition (E_ACT_TOO_MANY_ACTIVATIONS)

E_ACT_TOO_MANY_ACTIVATIONS

I am using the Adobe Digital Edition app on my phone. To my dismay, the app doesn't want to open my purchased e-book. To no avail, I googled how can I can open the acsm without using the Adobe Digital Edition app. I find out that I can use Aldiko app as an alternative. However, using another app didn't solve my problem. I cannot still open my e-book. Now, whenever I sign in to my Adob account, it only says  E_ACT_TOO_MANY_ACTIVATIONS. What should I do?