I have a supicion that this might be the bug in emClient where it just won’t work properly with AVG or AVAST email scanning active for Gmail account (and possibly others). I have experienced this personally here: Connection failed- red triangle - #8 by robross0606
A friend of mine had the problem actually (not me) and they ended up having to ditch emClient as they reinstalled AVG and it did not fix the problem and they were not willing to either a: turn off the email scanning in AVG or b: ditch AVG
It was a sad day for me because I recommended em Client v8 to them and it was all working just fine in em Client v7 then as soon as v8 was installed - BANG - it all went “pete tong” as they say.
ps: for those non english folk… "Pete Tong = “Wrong”.