ADE is very slow or crashed and I cannot import a normal e-book into ADE

Greetings to all of you. I have two problems with my Adobe Digital Edition (ADE) installed in my W10. Both these software are up-to-date.

First one: when I highlight sentences or simple words on my e-books, very often my ADE freezes/crashes. During these last days the situation is getting from bad to worse. Does anyone have any idea pls?

Second and last one: I cannot insert this e-book: Eleuteri_Provos_9788897747000 (_epub) into my ADE account. The reason on the scren: "ci sono errori in questo elemento"/there are mistakes in this element. IBS.it (the seller of the e-book) told me that by them all is ok, it is just a question of ADE. Does anyone know why?

Please let me know.

Many thanks in advance for your prompt attention and kind cooperation to these matters.