You need 10 KMD of interest earned in order to collect it. Had you earned 10 KMD when you recently tried?
Not now. Ok, will wait

But in the past I had once only about 11 KMD balance in my wallet and could collect interest amounts of 0.0xxx.
Thought it only had to be 10KMD or more in the wallet to get interest. For collecting interest, there is a limit, too?