Explorer Mode and Low-Light Distance dimming not working for a Player of mine

So can anyone explain how to fix this issue? When I preview as the Token, it works fine. Other players said their low-light distance for their light source as well as Explorer Mode is working fine.  I have one player we've been trying to troubleshoot with because he still sees every explored area as black no matter what browser he is using and no matter how many times we move his token to other areas to see if it works. His Low-Light distance is working only it's not dimming the light, it shows it as 100% (when we have it set to like 20%).  He was using Chrome but tested it with Firefox and it's still not working.  Anything else we can try? It's making the game experience horrible for him since he sees everything as black except for the lighted area he's in, he would like to see the Explored rooms but, again, it's not working. 

Hi Dungeon Master Ao,  Preview (Ctrl+L) is not a reliable test for Dynamic Lighting. It shows you what you the GM sees from the point of view of the token, not what your player will see from the point of view of the token. Similarly, rejoin as player has issues. Sometimes GMs assign themselves control over assets or the system gets confused as to which mode you are in.  The best method is to create a dummy account, use the dummy account in a different browser (or Incognito/Private mode if your main account is not in Incognito/Private mode). Then you assign the token/character to the dummy account.  Then you can set the two browsers side by side, make changes on the GM side, and see those changes on the dummy account side.  By using the dummy account setup above you can test to make sure that the settings are correct. That will tell us if the problem is with the settings or with the user's machine.  Please indicate where the problem is after testing.

Gauss said: Hi Dungeon Master Ao,  Preview (Ctrl+L) is not a reliable test for Dynamic Lighting. It shows you what you the GM sees from the point of view of the token, not what your player will see from the point of view of the token. Similarly, rejoin as player has issues. Sometimes GMs assign themselves control over assets or the system gets confused as to which mode you are in.  The best method is to create a dummy account, use the dummy account in a different browser (or Incognito/Private mode if your main account is not in Incognito/Private mode). Then you assign the token/character to the dummy account.  Then you can set the two browsers side by side, make changes on the GM side, and see those changes on the dummy account side.  By using the dummy account setup above you can test to make sure that the settings are correct. That will tell us if the problem is with the settings or with the user's machine.  Please indicate where the problem is after testing. I did as you suggested and the Dummy Account works fine with the lighting. The other players all say it looks fine also. It's just the one player, who is using Chrome and Firefox both, that is having the weird issues of the Explorer Mode not working and the Low Lighting effect.  Clearly it's the user's machine as you suspected. What can he do about it?

Make sure the user has Hardware Acceleration (renamed Graphics Acceleration in Chrom iirc) turned on.  Extensions should be off.  Make sure there are no invasive background programs (sometimes security programs get pretty invasive) If all those fail make sure they keep everything they can possibly turn off turned off, and the open tabs at the bare minimum to run Roll20.  Finally, if none of that works to resolve the issue, you should start turning things off. I'd start with Explorer Mode, then if that isn't enough move to the Low Lighting effect.  Sometimes people's machines are just not enough to run Roll20's more resource intensive features.