No taste for chanting after years of chanting?
There is a joke: one man prayed to God, "My Lord, I have heard that from Your point of view, millions of years are but a minute, and millions of dollars are hardly a penny. So could You kindly give me just one of Your pennies?" to which God replied, "Sure. Just a minute."
Whether we've been chanting for years or months or days doesn't matter from Krishna's point of view. It is to be expected that we will all eventually make spiritual progress, the more time and effort we put into our practice of chanting, but it should never be a cause for disappointment—although devotees often express disappointment in this regard—if we're not experiencing the spiritual bliss we think we should be experiencing after having chanted for some time.
Chaitanya Mahaprabhu Himself prays to Krishna—even though He is Krishna Himself—durdaivam idrisham ihajani nanuragah, "I am so unfortunate that I have no attachment for Krishna's names." He's acting as the prototype of all devotees, and lamenting that He has no attraction for chanting, while we know that He was experiencing the highest bliss imaginable. So if we're feeling unfortunate that we have no taste for chanting Hare Krishna, we should lament. Our chanting should be infused by that lamentation.
The principles taught by Srila Rupa Goswami in his excellent book Upadeshamrita, Nectar of Instruction, are always applicable. One is that we should always endeavor with patience, enthusiasm, while following the recommended process of devotional service. To chant while trying to become free from the offenses to chanting is our process. This effort itself will give us the taste we're looking for.
The primary offense in chanting is inattention. This is the offense from which all other offenses develop. For us to be able to begin to appreciate the qualities of the holy name, we need to do everything within our power to be able to chant with attention. Attention is the beginning of love. And the taste we're looking for in our chanting won't develop if we're letting our attention wander during our japa and not constantly trying to bring it back to hearing the mantra.
There are now quite a few books written on the subject of how to improve the quality of our chanting. You may wish to explore what they have to say, and see if you would like to incorporate any of the many tips they contain for helping focus the wandering mind on the chanting of Hare Krishna.