Do tell me about this. For him now!

No this is coincidental . It is not due to the solid feeds . You can continue the feeds . The fever must be due to some other cause like a viral infection etc . But remember that when a child is having some infection his appetite tends to go down so he may not show interest in feeding during that period . Don't take it as the food not suiting him . Besides Cerelac you can give well cooked dhuli daal, mashed banana , mashed potatoes ,  Khichdi, sooji Kheer etc Whatever you start : 1. It should be in very small quantities 1 to 2 tsf and gradually keep increasing the quantity over the next few days . 2. Never introduce more than one new food at one time . This will enable you to know which food doesn't suit the baby 3. 5 to 7 months period should be the one to introduce gradually most of the home based foods cooked in your home 4. The semi solid food given should be soft , mashed and easily swallowable by the baby .  But don't make a liquid out of it . That will not be good in the long run