See https://librenms.wikimedia.org/graphs/id=13969/type=port_errors/
Usual cable/optic swap, a complication is that the other side is a transit provider and the issue could be on their side. I still recommend checking our side first.
BGP to that peer needs to be disabled ahead of the onsite work.
Ideally to be added to T294968 but we should fix it sooner than latter (eg. max in the next month).
- 2022-06-15 - optic swapped and issue remains, need to escalate to Telia to check the link on their end.
- 2022-06-16 - Arelion support case 01418061 to investigate