What's meaning of "I KNOW FFS THANKS SOO MUCH , exucse my language"?

Question

There is a question on Server Fault: Job for httpd.service failed. Here is the answer and a comment.

Answer:

The key error message appears to be:

SSLCertificateFile: file '/etc/httpd/ssl/apache.srt' does not exist or is empty

Which is likely a small typo in /etc/httpd/conf.d/ssl.conf in the name of the SSL public key component of your certificate, most likely it should be apache.crt instead of apache.srt

You can see the comment under the answer.
Comment:

I KNOW FFS THANKS SOO MUCH , exucse my language

What mean of the "I know FFS"? And "exucse my language"?

Answer 1

I don't know the best way to punctuate this, but here is one way:

I know, FFS! Thanks so much! Excuse my language.

I'm not entirely sure what the I know does here, but I think it's simply an expression of agreement:

I know
said to show you agree with something someone has just said:
"But he's so awful." "I know - he's dreadful."
(Cambridge Dictionary)

FFS stands for for fuck's sake. It's an expression of frustration.

for fuck's sake
rude slang An expression of annoyance or frustration at what someone is doing or at a situation that is unfolding. Oh, for fuck's sake, Chris—you know I wasn't trying to hurt you, so stop acting like a wounded puppy. Stop playing your music so loud, for fuck's sake!
(TFD)

I don't know much about the topic, but it seems like he's frustrated that such a small error caused him such a huge headache.

Excuse my language just means that he's asking the respondent to excuse his usage of profanity.