Windows .crl to .pem for nginx
The error means that your crl file is not encoded properly in PEM format with right header and footer. Have the right PEM encoded crl file.
If the CRL is in DER format:
openssl crl -in your_current.crl -inform DER -out crl.pem
Now you can use crl.pem as you mentioned in question.
openssl crl -in crl.pem -noout -text