I am getting the following error: com.cloudmersive.client.invoker.ApiException: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

For this issue, you may need to add our certificate to your trust store. It is a public certificate, so normally this is automatically recognized, but if your servers is configured to not support public certificates by default, you may need to follow these steps:
You need to add the certificate for the application to the truststore file of the used JVM located at:

%JAVA_HOME%\lib\security\cacerts.

First you can check if your certificate is already in the truststore by running the following command:

keytool -list -keystore "%JAVA_HOME%/jre/lib/security/cacerts" 

(you don't need to provide a password)

If your certificate is missing, you can get it by downloading it with your browser and add it to the truststore with the following command:

keytool -import -noprompt -trustcacerts -alias ALIASNAME -file CERTIFICATE -keystore KEYSTOREFILE -storepass PASSWORD