Login as FIRSTLINE and go to:
https://admin.atlassian.com/s/d79bb9fc-6c6f-4963-8efd-2da266073c8e/users
here look for your user :
after selecting you can now see where the user has access
for example, for Andrew, he did not have access to jira and confluence
but by adding him to certain groups he can have access, for example seeing he is an APP support, I went and put him in the same groups as Stephan then immediately he had access to jira and conf.
stephan's groups