error Unable to configure verify locations for client authentication

Starting my apache2 Server on Ubuntu 12.04.5 LTS, I got the following error

[error] Unable to configure verify locations for client authentication

my Problem, on the server are more than one Client. so the question would be how to find out which client cert is doing a problem? As described on the Internet I excluded (on some client) the file calling up the cert but then the Apache2 Server said no valid cert and cert are needed.

at least would be nice if apache would start, also without cert. ;-)

have a nice day

Vinc

Check your certs are in .pem format (which is ASCII text) not .der format (which is binary). I mean actually open them and look at them, don't just look at the extensions.

The error you mention most often has to do with the SSLCertificateChainFile or the SSLCACertificateFile being unable to be read and parsed.

Source: http://docstore.mik.ua/orelly/weblinux2/apache/ch11_10.htm