Is it permissible for a woman to contact a competent dream interpreter if her husband does not approve of her contacting him, or should she have her dream interpreted by another, less competent interpreter who responds via WhatsApp?

A wife must obey her husband in matters related to marriage and family, unless it involves disobedience [to Allah]. This includes his forbidding her from speaking with non-mahram men, out of jealousy and protectiveness, as the Prophet (peace and blessings be upon him) said: "He forbade women from speaking [to men] except with their husbands' permission." There is no necessity to interpret dreams that would permit disobeying the husband. A bad dream should be sought refuge from and does no harm, and a good dream does not require interpretation. Therefore, it is not permissible for the wife to call someone who interprets dreams if she knows her husband rejects it. She can suffice with correspondence [e.g., text messages] or not interpret them at all.