Clients are interested in my proposals and do not tell me anything about the next step

[#1]

Hello dear community

I am new to the UpWork platform, but after sending my proposals to offers, some customers contact me and after exchanging messages on UpWork, they no longer respond to my messages.

The day before yesterday, I had a promise of call to ask my availability for interview, and after I gave my agreement, the client has not responded until today, to my messages where I asked for clarification on the time zone and other details on the interview. Today I even made the observation that this proposal is no longer part of my active proposals.

I would like to understand better