Now working for me too, thank you very much for fixing.
“ERROR: No config item” can’t get many settings to “stick” in the Global Configuration menu.
XXXXXX@netops:/opt/librenms $ sudo ./validate.php
| Component | Version |
|---|---|
| LibreNMS | 1.47-87-g45e0e5e19 |
| DB Schema | 1000 |
| PHP | 7.0.33-0+deb9u1 |
| MySQL | 10.1.37-MariaDB-0+deb9u1 |
| RRDTool | 1.6.0 |
| SNMP | NET-SNMP 5.7.3 |
====================================
[OK] Composer Version: 1.8.0
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct
[FAIL] The poller (raspberrypi) has not completed within the last 5 minutes, check the cron job.
The poller error is odd, because it is polling and I’m not sure what to check as it seems to be working just fine. I just can’t seem to update/change many config items on the Global Config menu.
Same issue on my side, fresh install according to the setup guide but the same “Error: No config item” popup on my install!
having this same issue on a clean install as well. is there any fix?
Even i am having a same issue on configuration of librenms on ubuntu 18. However it is working fine on ubuntu 16.
All with this issue please check Enabling Email alerts return "Error: No config item"
Thank you @TheGreatDoc 
Now i am able to solve that