Something else you could try is to limit the number of concurrent downloads to a number lower than the default of 10. This is located under NCM settings -> Config (see image below).
When we ran into this issue the CPU on our Solarwinds server was spiking close to 100%, we reduced the number of concurrent downloads to 5 and the timeout errors ceased. Once the server was upgraded we change it back to 10 and all is good now.
