Problem with use of “members” plugin in WordPress 4.9.8

I use the plugins
– “Members”(your plugin) to attach roles to users
– “WordPress access control” which attach roles to posts and pages and so the access to these pages (menus also) and posts is restricted to users which have the roles
When a user logs in there is the error message that I input below
My work-around is to activate your plugin only to create users with the roles and to deactivate it afterwards, and it seems a solution, but it is not very pleasant.
Can you tell me what can be done to avoid this thing ? Because your plug in with the other one, it is a very good thing to have a blog with a private section.
Thank you
==================================ERROR MESSAGE =============================
Warning: array_keys() expects parameter 1 to be array, null given in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #2 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #1 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_keys() expects parameter 1 to be array, null given in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #2 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #1 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_keys() expects parameter 1 to be array, null given in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #2 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #1 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_keys() expects parameter 1 to be array, null given in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #2 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51

Warning: array_merge(): Argument #1 is not an array in /homepages/6/d737435129/htdocs/clickandbuilds/Polycantus/wp-content/plugins/members/inc/functions-users.php on line 51