I'm unsure as to whether you're using the word 'transcript' correctly which, given the nature of your communication, would seem to be extremely important!
The definition of 'transcript' is 'a written or printed version of material originally presented in another medium'. [e.g. a transcript of a radio broadcast will have the words of the interview (or play, or whatever) typed out]. I don't know what 'transcript' means in your draft document and, if can't understand it, there's a very good chance that the recipient won't be able to either. So, irrespective of any other changes that might be needed, you need to substitute an alternative word there? (I can't actually suggest one though, precisely because I don't understand what it is that you're actually writing about!).
In both this document and previous emails you've written about, you've used the word 'professor' as an occupation. In English 'professor' tends to be only used as a title for the head of a university faculty (or a department within a faculty). e.g. 'Professor Jones' or 'Professor Fernandez'. It's not usually used to refer to an occupation; it would be more natural to refer to 'my tutor', 'my course leader' or 'the head of my faculty' than to 'my professor'.
As it stands, your proposed email seems very muddled. Something along the following lines might be better. (In the absence of any knowledge about what you actually mean by 'transcripts', I've substituted 'reports' but you might need to amend that):
"As per your request, I attach reports from the first and second semesters of my course at the University of Siegen.
My studies were made exceptionally difficult for me by an inadequate internet connection, together with some power outages, during many of my lectures. As a result, I was sometimes late in submitting my coursework, meaning that I was unable to attain the standard that I know I might otherwise have achieved.
My English language course was also hampered by a delay in receiving the text book upon which assignments were based. (I advised the course leader of this problem and I attach copies of my correspondence with him on this matter).
I hope that, by being able to attend future semesters in person, I will be able to put these problems behind me and go on to achieve the high standards in my coursework that I know I am capable of.
I hope for a positive response from your Embassy and I look forward to hearing from you soon"