Firefox for the browser?
I have been having some odd issues with Firefox and the website. The workaround is to delete your browers history, cache, temp files etc. and close out of the browser and restart it. This has worked for me with some of the odd glitches lately.
If it is another browser try the same steps, 9 out of 10 times this will clear up the issue. If it doesn't fix the issue then always a small chance something is off with your provider and how it is resolving the response back from the dns servers whether timing out or something else.
Your phone being a different browser and most likely connecting via that companies data/ dns servers it what leads me to think sum ting wong with the browser or your home ISP. (I work for one of the big cable companies)