X500 principal [CN=client] was not decoded - no values of attribute [2.5.4.3]

Debugging revealed certificate use utf8String representation whereas Elytron is expecting printableString

In rfc 5280 [1] chapter 4.1.2.4. Issuer there is specified value of subject/issuer can be of 5 types

   DirectoryString ::= CHOICE {
         teletexString           TeletexString (SIZE (1..MAX)),
         printableString         PrintableString (SIZE (1..MAX)),
         universalString         UniversalString (SIZE (1..MAX)),
         utf8String              UTF8String (SIZE (1..MAX)),
         bmpString               BMPString (SIZE (1..MAX)) }

However Elytron X500 principal decoder [2] can handle only 2 of them PRINTABLE_STRING_TYPE and IA5_STRING_TYPE (not sure which type of rfc does that match) [2]

Definitely missing utf8String (my case). Also revise for backward compatibility teletexString, bmpString and universalString

[1] https://www.ietf.org/rfc/rfc5280.txt
[2] https://github.com/wildfly-security/wildfly-elytron/blob/32ff7c17965b3ecae6be7ce1c9b96ab642ddc4ad/src/main/java/org/wildfly/security/x500/util/X500PrincipalUtil.java#L95