All right! I copied the _sign function over to the dns_transip.sh script. ( https://github.com/acmesh-official/acme.sh/blob/master/acme.sh#L1031-L1085 to be precise) and that seems to resolve the issue:
# pvenode acme cert renew
Loading ACME account details
Placing ACME order
Order URL...
Okay, that was my bad, I copy/pasted the wrong output. /transip.key is readable, yes (the problem was having quotes around the env var value).
# pvenode acme cert renew
Loading ACME account details
Placing ACME order
Order URL...
Hi,
I'm trying to setup Let's encrypt/ACME with the transip DNS plugin. Both automated and from the command line (pvenode acme cert renew) will have the dns_transip.sh script throw an error:
# pvenode acme cert renew
Loading ACME account details
Placing ACME order
Order URL...