Learn Italian: Il server cade spesso, non puoi contarci. - The server crashes often, you can't count on it.

In this context, ci means 'on it'. The Italian expression is contare su (to count on). Instead of saying contare su di esso, Italian uses the clitic pronoun ci, which naturally replaces su + an object or idea. To attach it to the infinitive verb contare, you just drop the final -e.

Could I put ci before the verb instead?

Yes! Because contarci follows the modal verb puoi (you can), you have a choice. You can attach ci to the end of the infinitive (non puoi contarci) or put it right before the conjugated modal verb (non ci puoi contare). Both are completely correct and mean the exact same thing.

Doesn't cadere normally mean 'to fall'?

Yes, the literal meaning of cadere is 'to fall'. However, in computing and telecommunications, Italian uses cadere the same way English uses 'to go down' or 'to crash'. You will also hear this with phone calls, such as è caduta la linea (the line dropped).

Why can't I just use lo (it) and say non puoi contarlo?