commands not opening in steam browser

[Cubix]

Hey there i was using a code so that when players type !addons the addons link will appear etc
in the steam browser i tried it on my test server it worked just fine but when i try to do it on my own server it did not work it gave me a white browser, How can i fix

[Cubix]

--- Links for ULX by Jackaralious

CATEGORY_NAME = "Links"

// Addons
function ulx.addons(ply)
ply:SendLua([[gui.OpenURL("http://steamcommunity.com/sharedfiles/filedetails/?id=771372269/")]])
end
local addons = ulx.command( CATEGORY_NAME, "ulx addons", ulx.addons, "!addons" )
addons:defaultAccess( ULib.ACCESS_ALL )
addons:help( "addons." )

// Forums
function ulx.website(ply)
ply:SendLua([[gui.OpenURL("https://bigserver.mistforums.com/")]])
end
local website = ulx.command( CATEGORY_NAME, "ulx forum", ulx.website, "!forum" )
website:defaultAccess( ULib.ACCESS_ALL )
website:help( "Forums." )

// Donate
function ulx.donate(ply)
ply:SendLua([[gui.OpenURL("https://bigserver.mistforums.com/donate/")]])
end
local donate = ulx.command( CATEGORY_NAME, "ulx donate", ulx.donate, "!donate" )
donate:defaultAccess( ULib.ACCESS_ALL )
donate:help( "Donate for some awesome ranks and perks!" )

C:\Users\customer\Desktop\test server\garrysmod\addons\ulx-master\lua\ulx\modules\sh