Can't delete user in FW XG

I got this error when trying to delete a user :

Couldn't delete user. A firewall rule, VPN connection, web policy rule, or SSL/TLS inspection rule exists for this user.

When looking at  applog.log and csc.log I got :

Jan 17 13:10:22Z apiInterface:: Deleting Entity and Event for legacy mode base operation
Jan 17 13:10:22Z Request type = 1
Jan 17 13:10:22Z apiInterface:versionsupported: true.
Jan 17 13:10:22Z apiInterface:request mode -> 33.
Jan 17 13:10:22Z apiInterface:Current ver :::'1900.1'
Jan 17 13:10:22Z apiInterface:entityjson::::::::identity::user=HASH(xxxxxxxxxxx)
Jan 17 13:10:22Z Info:: Transaction will not be rolled back for opcode delete_user. If any operation fails, request is part of multiple request :
Jan 17 13:10:22Z delete_userid failed for

and :

 ERROR Jan 17 13:02:23Z [delete_user:27765]: get_query_status: DB has returned error code: 23503
ERROR Jan 17 13:02:23Z [delete_user:27765]: get_query_status:Query Error: ERROR: update or delete on table "tbluser" violates foreign key constraint "tbluserrel_userid_fkey" on table "tbluserrel"
DETAIL: Key (userid)=(48) is still referenced from table "tbluserrel".
CRITICAL Jan 17 13:02:23Z [delete_user:27765]: csc_prep_query: execute_prepare_query failed for Execute Query.
ERROR Jan 17 13:02:23Z [delete_user:27765]: do_prep_query: Failed PREPSTMT: 'delete from tbluser where userId = ?'
ERROR Jan 17 13:02:23Z [delete_user:27765]: get_query_status: DB has returned error code: 25P02
ERROR Jan 17 13:02:23Z [delete_user:27765]: get_query_status:Query Error: ERROR: current transaction is aborted, commands ignored until end of transaction block
ERROR Jan 17 13:02:23Z [delete_user:27765]: csc_prep_query: execute_prepare_query failed for SELECT txid_current().
ERROR Jan 17 13:02:23Z [delete_user:27765]: delete_userid: input has no array elements
ERROR Jan 17 13:02:23Z [delete_user:27765]: delete_ugrel_cache: input has no array elements
WARNING Jan 17 13:02:23Z [delete_user:27765]: Action with NOFAIL Failed.

this was not helping : 

(+) Couldn't delete user. A firewall rule, VPN connection, web policy rule, or SSL/TLS inspection rule exists for this user. - Discussions - Sophos Firewall - Sophos Community

(+) Cannot remove AD user - Discussions - Sophos Firewall - Sophos Community

Have a nice day.