Unable to launch TCA GUI; API server supporting this page may be temporarily down,Please reload page

Symptoms-

While trying to lauch the Telco cloud automation GUI it says API server supporting this page may be temporarily down,Please reload page error.

Probable Causes of failure-

The web-engine service of the TCA appliance might be down.

Resolution-

1. Try restarting vCenter server.

2. You can start web-engine service manually by going to the Appliance Management UI (port 9443 - admin SSH credentials) and start the Web Service.

3. Alternatively, from the SSH session, drop down to root and start the service manually:

su -
systemctl restart web-engine

Reboot of appliance should auto-fix this.

4. Check the errors in the logs under:

/common/logs/admin

Check web.log and web-startup.log files and according actions can be performed.