Errors like this are logged. Check the error log on your server. If you can’t find the log, please contact your host.
Meantime, enable wp_debug and wp_debug_log and after an error, look at wp-content/debug.log to see if anything gets logged there. https://codex.ww.wp.xz.cn/Debugging_in_WordPress
You can also try this: Please attempt to disable all plugins, and use one of the default (Twenty*) themes. If the problem goes away, enable them one by one to identify the source of your troubles.
If you cannot access wp-admin, there are other ways to deactivate plugins.
How do I check the error log on my server? How do I find my server? How do I find see who my host is?
Sorry, I’m very new. Taking over an existing website
Who set up the site for you? Do you pay a monthly or annual bill for website hosting?
