Cannot access WP Admin

Hello, I recently added a website (eat-me-ltd.com) to my account. I installed upfront builder and created a website using the issue theme. I then installed market press to build a shop, I added 3 products successfully then logged off to come back to it today.

However I cannot access wp-admin anymore, I receive this message:
********* Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator, you@example.com 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 **************

The website still seems to be active but I can no longer access wordpress. Could this be a conflict with the plugins.

I would appreciate if you could please have a look.

Many thanks

Andrew