Router light was blue but could not connect to the internet

[#1]

the problems seems to be intermittent as I am now connected but earlier on  the router refused to connect. I tired restrung it and  the computer to little effect until it finally worked. I had noticed before that Safari pages would not load firs time and have to reload before whichever webpage I was looking for appeared but thirds was different because none of my devices worked despite the router light being solid blue .Does anyone have any suggestion what it could be as I think it may happen again?

[#2]

I forgot to add that the connect.  dropped  off on a number of occasions but connected within a couple of minutes or so .The difference then  was that the  light was solid yellow each time