Marketplace currently issues a certificate valid for only one year. The current certificate was renewed in early June 2017 and some different problems can happen:
Follow these steps to fix the problem
Download the certificate from Marketplace
On Chrome press F12 or click on the 3 dots menu -> More tools -> Developer Tools
On the top, select the Security tab
Click "View certificate"
When the certificate window shows, switch to "Details" tab and click on "Copy to File..."
Hit Next on the first window and select "Base-64 encoded X.509 (.CER)"
Finish exporting the file and save it as marketplace.cer (just to make the process easier)
Copy the certificate to ArcMC
Use scp, Winscp, Mobaxterm or a pendrive to copy the file into the /tmp folder on the server
Copy the file to their destination
Replace <ARCMC_DIR> with:
Run as root
cp /tmp/marketplace.cer <ARCMC_DIR>/arcmc/config/certs/marketplace.saas.hpe.com chmod 0750 <ARCMC_DIR>/arcmc/config/certs/marketplace.saas.hpe.com
cp /tmp/marketplace.cer <ARCMC_DIR>/arcmc/config/certs/marketplace.saas.hpe.com
chmod 0750 <ARCMC_DIR>/arcmc/config/certs/marketplace.saas.hpe.com
Restart ArcMC Web Process
<ARCMC_DIR>/arcmc/bin/arcmcd restart web
/opt/local/monit/bin/monit restart web
Yes I read this post and performed those steps several times. But were unsucessful still is fixing the error.
Be sure to make a backup of the old cert. When I followed these steps, the web service refused to start with the new cert in place. Ended up coping the expired one over the new one to get access to the web GUI again.