Source: The Great Interpretation of Dreams (Ibn Sirin)
Giving the Adhan in the bathroom indicates disrespecting religion or severe illness.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
Giving the Adhan in the bathroom indicates fever or ugly speech.
Source: Signs in the Science of Expressions (Ibn Shaheen)
Giving the Adhan in the bathroom is interpreted as worry and illness.