TrustedCA import cert to solve PKIX path building failed error

Below show example error of PKIX path building failed when do a REST HTTP call and how to solve it:
Error message:

Go to website that the do REST HTTP call, this is firefox browser, click that:

More:

View Certificate:

Detail, Export:

Save to folder:

Go to NWA, Key Storage, choose TrustedCAs, Import Entry:

Choose below and browse to the cert file, then import:

Cert imported:

Reprocessing, now REST HTTP call is success!

All the best to myself!