"this class is not key value coding-compliant for the key" although the outlets are connected

Question

I have a custom UIView class named CustomMarkerInfoWindow with .h, .m and xib files.

In the xib file I have 2 labels called storeNameLabel and storeAddressLabel that I've connected to CustomMarkerInfoWindow as 2 IBOutlets.

For some reason, when I try to create a object like this:

CustomMarkerInfoWindow *infoWindow=[[[NSBundle mainBundle] loadNibNamed:@"CustomMarkerInfoWindow" owner:self options:nil] firstObject];

the app crashes and I get this crash message:

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<AroundersViewController 0x7fed34820400> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key storeAddressLabel.'
*** First throw call stack:
(
    0   CoreFoundation                      0x0000000108ad7d85 __exceptionPreprocess + 165
    1   libobjc.A.dylib                     0x000000010854bdeb objc_exception_throw + 48
    2   CoreFoundation                      0x0000000108ad79c9 -[NSException raise] + 9
    3   Foundation                          0x000000010811619b -[NSObject(NSKeyValueCoding) setValue:forKey:] + 288
    4   UIKit                               0x0000000109020d0c -[UIViewController setValue:forKey:] + 88
    5   UIKit                               0x00000001092577fb -[UIRuntimeOutletConnection connect] + 109
    6   CoreFoundation                      0x0000000108a11890 -[NSArray makeObjectsPerformSelector:] + 224
    7   UIKit                               0x00000001092561de -[UINib instantiateWithOwner:options:] + 1864
    8   UIKit                               0x0000000109258415 -[NSBundle(UINSBundleAdditions) loadNibNamed:owner:options:] + 223
    9   Arounder                            0x0000000104c90fbf -[AroundersViewController mapView:markerInfoWindow:] + 159
    10  CoreFoundation                      0x00000001089c05cc __invoking___ + 140
    11  CoreFoundation                      0x00000001089c041e -[NSInvocation invoke] + 286
    12  CoreFoundation                      0x0000000108a4fd26 -[NSInvocation invokeWithTarget:] + 54
    13  Arounder                            0x0000000104e66227 -[GMSDelegateForward forwardInvocation:] + 102
    14  CoreFoundation                      0x0000000108a26b17 ___forwarding___ + 487
    15  CoreFoundation                      0x0000000108a268a8 _CF_forwarding_prep_0 + 120
    16  Arounder                            0x0000000104de1853 -[GMSMapView infoWindowForMarker:] + 74
    17  Arounder                            0x0000000104ddd863 -[GMSMapView setSelectedMarker:] + 514
    18  Arounder                            0x0000000104ddef93 -[GMSMapView didTapMarker:] + 100
    19  Arounder                            0x0000000104e25296 -[GMSMarker wasTapped] + 57
    20  UIKit                               0x0000000109385b28 _UIGestureRecognizerSendTargetActions + 153
    21  UIKit                               0x000000010938219a _UIGestureRecognizerSendActions + 162
    22  UIKit                               0x0000000109380197 -[UIGestureRecognizer _updateGestureWithEvent:buttonEvent:] + 843
    23  UIKit                               0x0000000109388655 ___UIGestureRecognizerUpdate_block_invoke898 + 79
    24  UIKit                               0x00000001093884f3 _UIGestureRecognizerRemoveObjectsFromArrayAndApplyBlocks + 342
    25  UIKit                               0x0000000109375e75 _UIGestureRecognizerUpdate + 2634
    26  CoreFoundation                      0x00000001089fcc37 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
    27  CoreFoundation                      0x00000001089fcba7 __CFRunLoopDoObservers + 391
    28  CoreFoundation                      0x00000001089f27fb __CFRunLoopRun + 1147
    29  CoreFoundation                      0x00000001089f20f8 CFRunLoopRunSpecific + 488
    30  GraphicsServices                    0x000000010b784ad2 GSEventRunModal + 161
    31  UIKit                               0x0000000108e8df09 UIApplicationMain + 171
    32  Arounder                            0x0000000104cb2cef main + 111
    33  libdyld.dylib                       0x000000010a56192d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

the important part: this class is not key value coding-compliant for the key storeAddressLabel (and if I remove storeAddressLabel its crashes with the same error about storeNameLabel).

I've searched for hours for solution (I've tried to reconnect the outlets in a couple of ways, tried to recreate the class itself...).

Note: I've already checked this question but it's not working for me.

I really have no idea why it is happenning, can someone please help me?

Thank you!