Json parse error on login prevents user from login

Error: JSON.parse: unexpected character at line 1 column 1 of the JSON data

fromJson@http://172.23.107.8:8091/ui/libs/angular.js:1271:9

defaultHttpResponseTransform@http://172.23.107.8:8091/ui/libs/angular.js:9460:1

transformData/<@http://172.23.107.8:8091/ui/libs/angular.js:9551:12

forEach@http://172.23.107.8:8091/ui/libs/angular.js:340:11

transformData@http://172.23.107.8:8091/ui/libs/angular.js:9550:3

transformResponse@http://172.23.107.8:8091/ui/libs/angular.js:10319:21

processQueue@http://172.23.107.8:8091/ui/libs/angular.js:14792:28

scheduleProcessQueue/<@http://172.23.107.8:8091/ui/libs/angular.js:14808:27

$RootScopeProvider/this.$get</Scope.prototype.$eval@http://172.23.107.8:8091/ui/libs/angular.js:16052:16

$RootScopeProvider/this.$get</Scope.prototype.$digest@http://172.23.107.8:8091/ui/libs/angular.js:15870:15

$RootScopeProvider/this.$get</Scope.prototype.$apply@http://172.23.107.8:8091/ui/libs/angular.js:16160:13

done@http://172.23.107.8:8091/ui/libs/angular.js:10589:36

completeRequest@http://172.23.107.8:8091/ui/libs/angular.js:10787:7

requestLoaded@http://172.23.107.8:8091/ui/libs/angular.js:10728:1

consoleLog/<()angular.js (line 12520)

$ExceptionHandlerProvider/this.$get</<()angular.js (line 9292)

mnExceptionReporter/<()mn_exce...rter.js (line 19)

processQueue()angular.js (line 14800)

scheduleProcessQueue/<()angular.js (line 14808)

$RootScopeProvider/this.$get</Scope.prototype.$eval()angular.js (line 16052)

$RootScopeProvider/this.$get</Scope.prototype.$digest()angular.js (line 15870)

$RootScopeProvider/this.$get</Scope.prototype.$apply()angular.js (line 16160)

done()angular.js (line 10589)

completeRequest()angular.js (line 10787)

requestLoaded()angular.js (line 10728)

[undefined]

return logFn.apply(console, args);