A phone is read as the wish to reach someone, or to be reached. A call that will not connect is a classic picture of something left unsaid. Dialling wrong numbers or fighting a broken screen is one of the most common versions, read as frustration at not getting through to someone in waking life. A phone ringing that you cannot answer points to a message you are avoiding. A call from someone who has died is traditionally taken as memory and unfinished feeling rather than contact. Losing your phone is read as fear of being cut off.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.