Unfortunately this problem has been present for almost 5 years now. We called a good amount of people some experts, some just love computers, to help fix it, but no luck.
Don't really know what triggered it to stop working but it might've been a new device entering & connecting. Now, there is a macbook & any iPhone 5 or over that can connect to the wifi, but under 5 does not & most androids especially older ones cannot. Many older laptops do not either. The acer laptop we have that is only 2-3 years old does not. We tried switching modems, routers, & even internet providers. No help. The thing is, the old devices cannot even see the wifi on their connections list. Sometimes once in a blue moon but it never connects. There have been at most 3 rare times that it started to connect, once was quite random, & another time was when another old android entered the house & randomly connected in the basement, leading a few of the other old devices nearby to connect. It was on & off connection, & eventually stopped. It's honestly very bizarre. It seems like an internal issue, but we don't know what.
If it helps, our modem & router are on the main floor.
Pleeeease! Someone help!
Added (1). Please give me directions to what I can do or direct me to a link or video that can help me solve the issue.
Read more: Only newer devices can connect to wifi, not older ones?