If Ruby is not suitable it could have effects like you might have a headache.
The side effect of Ruby could be on your health, nature, attitude. You might feel laziness, problem in walking and sometimes you will feel tired. If Ruby is not suitable you will definitely wake up late in the morning. You will feel sleeplessness.
Other than this Sun will give the bad effect of the house in which Sun exists in your horoscope. For example, if Sun is situated in 5th house you will have relationship issues and in worse you might have break up with your partner. If you are a student you might feel no interest in studies.