I had to do a factory reset on my phone. This seemed to solve the problem at first. Though the problem came back and then went away again after I restarted my phone again. I don't know what the problem was originally or why it works sometimes but not other times.
@zeedjz I was trying to bypass that problem for you cause a factory reset deletes everything on your phone. if you check the APN type it should say MMS,default,supl so if this problem persists you can check that out. this is a known issue with the LG G5. also you can try to default your APN settings