Why Dont My Links Work?

Hello, i am rather new so im sorry if this is a silly question however this is my problem.

I have a wp website with its own domain name, rather than have 50 pages each relevant to a differant county i decided to set up sub domains for each area for example:

kent.blarblar.co.uk
london.blarblar.co.uk
essex.blarblar.co.uk

in each sub domain i have added a landing page rich with information specifically for that county, i had intended to link the “about us” “prices” etc etc to my main domain however the links will not work. the message i get is this;

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, [email protected] and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

I am really confused and have tried very hard to find a suitable and easy to understand solution but have failed. I would greatly appreciate any help anyone could offer me at this point.

Kind Regards
Stan