1. Are you still able to connect to the internet ?
2. Have you unplugged your router from its power source, waited 30 seconds then replugged? (this resets the DNS address to its original, one usulaly helping. This also ensures that the router has up to dat software it needs to keep functionning)
3. Log into the modem, you will find different frequencies
If your answer to 1, is yes then disregard the bulb may be burning out. If it is no then you proceeded to step 2, if this failed, try step 3. If all these fail to fix your issue your router is on it way out, and you will require a new one