If you REALLY want a working checker.

[xxxGargamelxxx]

....but want to sacrifice the speed, heres the settings.
Make sure to put your settings.json as READ ONLY or it will not work. I have not had an error since, however, this makes your checker pretty slow.
UPDATED TO 2019!
REMEMBER TO PUT THE CONFIG READ ONLY!
{
"ShowPasswords": false,
"SelectedRegion": 0,
"ClientConfig": {
"ProdGameClientVersion": "8.24.19_01_17_15_41",
"PBEGameClientVersion": "8.24.19_01_17_15_41",
"ProdHttpClientVersion": "18.0.0",
"PBEHttpClientVersion": "18.0.0",
"ProdGameClientRsoToken": "eyJhbGciOiJSUzI1NiJ9.eyJhdWQiOiJodHRwczpcL1wvYXV0aC5yaW90Z2FtZXMuY29tXC90b2tlbiIsInN1YiI6ImxvbCIsImlzcyI6ImxvbCIsImV4cCI6MTYwMTE1MTIxNCwiaWF0IjoxNTM4MDc5MjE0LCJqdGkiOiIwYzY3OThmNi05YTgyLTQwY2ItOWViOC1lZTY5NjJhOGUyZDcifQ.dfPcFQr4VTZpv8yl1IDKWZz06yy049ANaLt-AKoQ53GpJrdITU3iEUcdfibAh1qFEpvVqWFaUAKbVIxQotT1QvYBgo_bohJkAPJnZa5v0-vHaXysyOHqB9dXrL6CKdn_QtoxjH2k58ZgxGeW6Xsd0kljjDiD4Z0CRR_FW8OVdFoUYh31SX0HidOs1BLBOp6GnJTWh--dcptgJ1ixUBjoXWC1cgEWYfV00-DNsTwer0UI4YN2TDmmSifAtWou3lMbqmiQIsIHaRuDlcZbNEv_b6XuzUhi_lRzYCwE4IKSR-AwX_8mLNBLTVb8QzIJCPR-MGaPL8hKPdprgjxT0m96gw",
"PBEGameClientRsoToken": "eyJhbGciOiJSUzI1NiJ9.eyJhdWQiOiJodHRwczpcL1wvYXV0aC5yaW90Z2FtZXMuY29tXC90b2tlbiIsInN1YiI6ImxvbCIsImlzcyI6ImxvbCIsImV4cCI6MTYwMTE1MTIxNCwiaWF0IjoxNTM4MDc5MjE0LCJqdGkiOiIwYzY3OThmNi05YTgyLTQwY2ItOWViOC1lZTY5NjJhOGUyZDcifQ.dfPcFQr4VTZpv8yl1IDKWZz06yy049ANaLt-AKoQ53GpJrdITU3iEUcdfibAh1qFEpvVqWFaUAKbVIxQotT1QvYBgo_bohJkAPJnZa5v0-vHaXysyOHqB9dXrL6CKdn_QtoxjH2k58ZgxGeW6Xsd0kljjDiD4Z0CRR_FW8OVdFoUYh31SX0HidOs1BLBOp6GnJTWh--dcptgJ1ixUBjoXWC1cgEWYfV00-DNsTwer0UI4YN2TDmmSifAtWou3lMbqmiQIsIHaRuDlcZbNEv_b6XuzUhi_lRzYCwE4IKSR-AwX_8mLNBLTVb8QzIJCPR-MGaPL8hKPdprgjxT0m96gw",
"AuthRetries": 2,
"ConnectionTimeoutSeconds": 30
},
"DataDragonVersion": "9.3.1",
"DefaultCustomExportFilename": "DefaultText.txt",
"CheckForPenaltyTime": true,
"BanDaysToIgnore": 15,
"Workers": 4,
"MinSecondsDelay": 13.0,
"MaxSecondsDelay": 15.0
}
Or download the full checker here:

UPDATED TO 2019!
Don't Be Leecher