At the Oujda branch, the ERP opens but reports and file copies stay stuck

Rif Frigo Transports, a refrigerated transport company, has its head office in Tangier (network 10.1.0.0/16) and a branch in Oujda (network 192.168.60.0/24, 15 workstations). Until Friday, the branch was connected to head office by a leased line. This weekend, the contractor replaced it with an Internet fibre connection and a site-to-site IPsec tunnel: in Oujda, the gateway is gw-oujda (Debian 12, strongSwan), behind the operator's box (PPPoE); at head office, the head office firewall. The contractor validated the migration with a ping to the ERP (10.1.0.20): “everything answers”.

On Monday morning, the branch calls: the web ERP opens, the home page displays… but the route reports never load, the copy of scanned delivery notes to \\fs-tanger\agences stays stuck at 0 %, and remote desktop freezes as soon as a window redraws. The trucks leave without their documents.

You are a level 2 network administrator, logged in as root on gw-oujda. Get the traffic through, without going back to the old line (cancelled) and without touching the head office firewall (another team).