airplay speaker cannot connect to windows iTunes

Heelo,

the airplay icon desappears regularly from itunes (windows version) and when appearing, cannot connect to an airplay speaker. I have this problem for the last 2 to 3 months. I use windows 1803. Latest itunes for windows version 12.9.1.4. The airplay speaker is the libratone Zipp model 10137C. Before I never had any problem connecting the speaker from my computer. But now, it has become very frustrating. PLease help.