Help with error:14094416:SSL routines:SSL3_READ_BYTES:sslv3 alert certificate unknown

[Coeus[TM]]

Already asked for their mod_ssl.log. Going to post it once they sent it.

I only have the snippet below from their shibd.log

11:21:25.297 - INFO [Shibboleth-Access:73] -
20120203T055125Z|101.11.111.1|fooidp.net:443|/profile/Shibboleth/SSO|
11:21:27.318 - INFO
[edu.internet2.middleware.shibboleth.common.security.MetadataPKIXValidationInformationResolver:802]
- PKIX validation info cache cleared
11:21:27.318 - INFO
[edu.internet2.middleware.shibboleth.common.security.MetadataPKIXValidationInformationResolver:802]
- PKIX validation info cache cleared
11:21:41.577 - INFO [Shibboleth-Access:73] -
20120203T055141Z|101.11.111.1|fooidp.net:443|/profile/Shibboleth/SSO|
11:21:41.610 - INFO [Shibboleth-Audit:714] -
20120203T055141Z|urn:mace:shibboleth:1.0:profiles:AuthnRequest||https://foosp.net/shibboleth-sp|urn:mace:shibboleth:2.0:profiles:saml1:sso|https://fooidp.net/idp/shibboleth|urn:oasis:names:tc:SAML:1.0:profiles:browser-post|_m68dgh663f6263e8741d816fe8ca742z|foouser@foouser.org|urn:oasis:names:tc:SAML:2.0:ac:classes:PasswordProtectedTransport||_77774ded31fcca7777d448625eb17777|_77777e6be1c2eeb77777a90ffd977777,|

They also advised me to read the link below and suggested to apply the
workarounds (OpenSSL re-enable "unsafe" or upgrade or downgrade
version):
https://wiki.shibboleth.net/confluence/display/SHIB2/SSL+Renegotiation

This would be my last option.