SQL DateTime format is ISO: it is always yyyy-MM-dd HH:mm:ss.
Check where you are getting your date string from: the example in the error message is not in ISO format.
Keep DateTime information in DateTime variables: don't convert it to string, and especially, don't convert it to string to pass it to MySQL: use a Parametrized Query and pass it as a DateTime. Then you can't have any format conversion errors!
"please see my updates"
What did I say about Parametrized Queries?
Your code is the problem:
' as DTquality ,'" + DateTime.FromFileTime(e8.sts[counter8].TimeStamp) + "' as DTtimestamp ,'"
FromFileTime returns a DateTime, which your code causes to have an implicit ToString() method added in order to concatenate the strings.
This is where your problem is.
Change the way you build your query. Do not concatenate strings: it wastes memory and leave you wide open for anm SQL Injection attack which could accidentally or deliberately destroy your database, as well as cause your error.
If you convert this to Parametrized queries, your error will disappear!