Error 500--Internal Server Error

Okie-dokie ... this is probably a moot (specifically unanswerable) question, but I did a search here, to no avail.

I'm getting this error message upon trying to make an online purchase:

Error 500--Internal Server Error
From RFC 2068 Hypertext Transfer Protocol -- HTTP/1.1:
10.5.1 500 Internal Server Error

The server encountered an unexpected condition which prevented it from fulfilling the request.

Is there a good site somewhere that breaks-down, sort of "Maps-out", like a Flow-Chart or something, of how internet traffic is handled, and dispersed (i.e "Web Server">"ISP">"client",>etc.,>etc. ->->->?<-<?-?>->-?<->??!!??)

It's all a bit mystical (VIRTUAL) for me ...

 

Thanks very much!

Ok, you said "hesitate" ... now, I am trying to be less "technical" these days (in my speech, anyway), so, am I to understand there is a 'caveat to your caveat' ... :-D

No seriously, are you interested to say why you would hesitate and/or NOT order from this site?

Thanks again,
glenn ...