Sending POST returns 405 while my routes are OK

I have a weird problem. I try to log in with POST (username/password) to my application with this route

Route::post('login', 'AuthController@postLogin')->name('login.post');

I get a 405

The POST method is not supported for this route. Supported methods: GET, HEAD

In the local development environment everything is fine. In a production server environment I get this error.

I use Postman fos testing.

This is my route list

• GET|HEAD | /
• GET|HEAD | domains
• GET|HEAD | login
• POST | login
• GET|HEAD | research-programs
• GET|HEAD | researchers
• GET|HEAD | researchers/profile
• PUT | researchers/profile
• POST | researchers/profile/picture
• GET|HEAD | researchers/random
• GET|HEAD | researchers/search
• GET|HEAD | researchers/{id}
• PUT | researchers/{id}
• POST | researchers/{id}/picture
• GET|HEAD | units

I added a GET /login route and dumped the \Illuminate\Http\Request object to see what I got.

These lines tell me that there is a redirect?

"REDIRECT_REDIRECT_REDIRECT_STATUS" => "200"

"REDIRECT_REDIRECT_REDIRECT_UNIQUE_ID" => "ZQ27NKn65K-juEgBrlpqKgAAAMw"

"REDIRECT_REDIRECT_REDIRECT_URL" => "/login/"

"REDIRECT_REDIRECT_REQUEST_METHOD" => "POST"

"REDIRECT_REDIRECT_REQUEST_SCHEME" => "https"

"REDIRECT_REDIRECT_REQUEST_URI" => "/login/?XDEBUG_SESSION_START=PHPSTORM"

"REDIRECT_REDIRECT_SERVER_PORT" => "443"

"REDIRECT_REDIRECT_SERVER_PROTOCOL" => "HTTP/1.1"

"REDIRECT_REDIRECT_STATUS" => "500"

...

"REDIRECT_REDIRECT_UNIQUE_ID" => "ZQ27NKn65K-juEgBrlpqKgAAAMw"

"REDIRECT_STATUS" => "500"

"REDIRECT_UNIQUE_ID" => "ZQ27NKn65K-juEgBrlpqKgAAAMw"

"REDIRECT_URL" => "/500.shtml"

"REMOTE_PORT" => "54560"

"REQUEST_METHOD" => "GET"

"REQUEST_SCHEME" => "https"

This is my api.php

Route::get('/', function(){
   return "welcome";
});
Route::post('/login', 'AuthController@postLogin')->name('login.post');
Route::get('/researchers', 'ResearcherController@allResearchers')->middleware('admin');
Route::get('/researchers/search', 'ResearcherController@searchResearchers');
Route::get('/researchers/random', 'ResearcherController@randomResearchers');
Route::get('/researchers/profile', 'ResearcherController@getOwnData')->middleware('authenticated');
Route::put('/researchers/profile', 'ResearcherController@putOwnData')->middleware('authenticated');
Route::post('/researchers/profile/picture', 'ResearcherController@changeOwnPicture')->middleware('authenticated');
Route::get('/researchers/{id}', 'ResearcherController@getResearcher');
Route::put('/researchers/{id}', 'ResearcherController@putResearcher')->middleware('admin');
Route::post('/researchers/{id}/picture', 'ResearcherController@postResearcherPicture')->middleware('admin');
Route::get('/domains', 'DomainController@getDomains');
Route::get('/faculty-thematics', 'FacultyThematicController@getFacultyThematics');
Route::get('/research-domain-thematics', 'ThematiqueDomaineRechercheController@getThematiqueDomaineRecherche');
Route::get('/research-programs',  'ResearchProgramController@getResearchPrograms');
Route::get('/search-axes',  'SearchAxeController@getSearchAxes');
Route::get('/units', 'UnitController@getUnits');

I've been struggling with this for hours now.