Hello,
1) Login credentials that you provided do not work. Please, check the login and password and provide the correct one to allow our support team to do their job!
2) In case Internal server error appears then the fatal error should be in the server error logs. Internal server error does not appear without it. If you are a programmer of over 25 years you probably know this. So, make a double check of the server error logs.
Also, we use default PHP functions to check the memory limit. You can also go to WooCommerce > Status > check what the limit WooCommerce plugin detects. WooCommerce plugin is developed by another company.
Waiting for correct access to your WP Dashboard.
Regards