I've a few S7 antminer. They used to work fine but one of them stopped working.
I went through the configuration and noticed that the URL address for the pool (i used: stratum+tcp://stratum.f2pool.com:3333) was blank.

I inserted but could NOT 'Save and Apply'. It just becomes blank again. My previous typing goes blank...
I changed the PSU (providing 2.4kw - i know, overkill), but does not work.

I checked the fans, both are still working fine.

This simple issue of 'save and apply' the URL just does not work....driving me bonkers.... hope anyone out there can assist....