Looking for explanations to ML390S ERROR= codes please

Well, the unit's laser lense was replaced only a few months ago and it worked just fine until just now. 
The technician says "only the designer of the software would know" (if after 25 years he'd be still around...?!?) 
Contacting Harman seems questionable at best, also since I'm residing in RSA. 

The distributor wants to sell new stuff, and points me to his now freelance technician - who doesn't know, as already mentioned. 
Maybe I'll play the 'offending' CDs on my dirt cheap LG Blue Ray Player by using Toslink going into my ML36 DAC.?!? 🥴 
I keep my CDs *very* clean, and also it seems to have something to do with the 'quality' of SACD/CD discs... 
M. 🇿🇦 

Thanks for the kind responses,
one more curious thing to mention is, when opening the load-tray and rotating the CD by a few degrees it sometimes plays just OK right through.
Additionally by trying a few restarts, can also do the trick... 
 
However,
I feel that knowing what exactly those two error codes (7 and 10) try to communicate, might help explain what actually is the case when the disc is being refused, by the message displayed: 'NO DISC' ? 
M. 🇿🇦