Adding translation to a custom module I cannot make the module translation strings to be considered, unistalling and installing the module again.

Is the indicated .po relative path correct?

in my module blockForm function i have : 

  $form['retrieval_method'] = array(
    '#type' =&gt; 'fieldset',
    '#title' =&gt; $this-&gt;t('Retrieval Method'),
  );


my .info.yml

name: 'amu hal'
type: module
description: display publications from HAL
core: 8.x
version: 8.x-3.0
package: AMU
project: 'amu_hal'
interface translation project: amu_hal
interface translation server pattern: modules/amu_hal/translations/%language.po


and in


  /sites/mysite/modules/amu_hal/translations/fr.po :


msgid "Retrieval Method"

msgstr "Méthode d'extraction"


i have activated the core interface traduction module and the 


  /fr/admin/reports/translations


tells me Missing translations for 11 projects:


amu hal (8.x-3.0). File not found at modules/amu_hal/translations/fr.po
Thanks to comments and doc , i have moved the whole module in modules/custom/ and for info file: 

name: 'amu hal'
type: module
description: display publications from HAL
core: 8.x
version: 8.x-3.0
package: AMU
project: amu_hal
'interface translation project': amu_hal
'interface translation server pattern': modules/custom/amu_hal/translations/amu_hal-%language.po


Placing the po file at


  modules/custom/mymodule/translations/mymodule-fr.po


now i could update the translation at 


  /fr/admin/reports/translations


and make string translations

Note that the same po file is not found if the module is placed in sites/mysite/module