Electrical continuity between Ethernet ports, but no internet connection?

I have a cable running from a switch to a bedroom, terminated at each end in punchdown jacks (pictures attached of each jack). I’ve confirmed the electrical continuity is fine (details below), but I can’t get an internet link / lights at the switch. Everything is wired as T568A.

Topology:

Router - switch - patch cable 1 - punchdown jack 1 - cat6 cable - punchdown jack 2 - patch cable 2 - laptop

Troubleshooting I’ve tried:

• changed jacks
• loop back test with cable only; twisted the coloured pairs at one end and check closed circuit with a multimeter at the other. No issues.
• loop back test with jacks in place; made two male RJ45 cables with stripped ends. Plugged one into punchdown jack 1 and twisted the coloured pairs. Plugged the other into punchdown jack 2 and checked the circuits closed with a multimeter. No issues.
• replaced patch cables

At a loss of what to try next. Any ideas?

Punchdown jack 1:

Punchdown jack 2:

1. Check for shorts.
2. Check continuity not just on the cables but on the jacks. (Use a simple cable tester, or plug patch cables and measure between cable connectors.)
3. Make sure you're using a proper LSA+ tool - punching down using 'alternate' tooling may look OK but often isn't.
4. Make sure your pairs are kept intact (from the photos that one looks fine).
5. Make sure your jacks are suited for the cable type and AWG - usually you run solid-core cable between jacks/panels, not flexible, stranded cable.