Unable to Connect in Minecraft

My friend and I have a world that he created in Windows 10 Minecraft in which we have been working on for almost 6 months. I had been playing on Xbox before I moved into my college dorm. Shortly after I moved in, we tried to play together and I got the
Unable to Connect to World screen. We had encountered this before and it had been a quick fix of restarting our devices and then it worked. Sometimes, that wouldn't work and we would wait a day then the problem fixed itself. Our current problem, however, has
lasted 2 weeks. I have been able to play Minecraft with other friends who play on Xbox and have been able to play online in Forza and Sea of Thieves. I have also tried to connect to his world through pocket edition and Windows 10 to no avail. We are on the
same version and have been able to join servers together. I have searched and searched through multiple web forms and websites but no solution they proposed has worked. Another friend was able to join the world, which makes me believe it is on my end, not
his. Minecraft is the only game that online hasn't worked properly since I moved into my dorm, in which I use an ethernet cable, not WiFi. Any solutions to this very annoying problem?

:)