After installing PRTG and scanning my network, I got the following alert: 

(003)ixp0 Down No response (check: firewalls, routing, snmp settings of device, IPs, SNMP version, community, passwords etc) (SNMP error # -2003)

First, check if the SNMP Settings (Version, Community String, port, eventual authentication, etc.) are correct. Then please also check if PRTG (or the PC on which PRTG is installed) is allowed to send SNMP Requests to the device in case. You can also use our SNMP Tester to test the SNMP-Functionality on the target device(s).


However, there is no generic solution for it. The error message shown No response [...] (SNMP error # -2003) indicates a timeout and/or that PRTG is not able to receive the requested information via SNMP.


You need to verify that SNMP is properly configured on the monitored device and also configure the incoming SNMP communication from PRTG's perspective properly.


To do so, please open the Settings tab of the device that has the affected sensor and configure the required SNMP settings under Credentials for SNMP Devices.


Please check this article as well: My SNMP sensors don’t work. What can I do?


Disclaimer:
The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.