There are several reasons:
1) The amount of mining rewards you earned is too small. Our asset field displays three digits after the decimal point and the number won’t show if it is too small;
2) You have just staked your tokens, and the number won’t be displayed immediately. So please wait patiently until the information shows;
3) You have just supplied your tokens, and the number won’t be displayed immediately. It will be shown in 24-72 hours. Please wait patiently.