A 403 means: your account has no access to this action. Possible causes:
1. Wrong role — Manager is missing a toggleable permission. Ask Admin to turn it on under Admin → Users → Role permissions.
2. Client restriction — as Manager you only see assigned clients. Ask Admin to assign you.
3. Tenant mismatch — old bookmark points to another agency. Log out and log back in.
4. Sales role trying to open a client or financial page — those are not available for sales.
Think this is unjustified? Contact your agency owner.