Problems with my theme

Hi!

I tried to fix it by myself, read the tutorial, but I just don’t get it to look nice. In addition, my menu disappears as soon as I open the list or calendar view. I have no idea what’s wrong.
I’m using the Beach Please theme by Apollo13.

My problems in detail in list and list/calendar view:
– the website’s main menu (on the left side) disappears (I mean the links, the menu table is still there)
– the whole design is too wide and too close to the browser’s borders (especially on the left)

My problems in detail with single events:
– the whole design is too wide and too close to the browser’s borders (especially on the left, but I solved it with vertical tabs). I’m talking about the headline, the date, the link back to calendar/list view, description, featured image and the “+ Google Calendar” button etc. -> nothing is centered. 🙁

And these two things could be bugs:
– The website at “event location” (I’m not sure if this is the correct labeling as I’m using the German version) doesn’t become a link. See here.

– the “+ Google Calendar” button always leads to this error:

414. That’s an error.

The requested URL /calendar/event… is too large to process. That’s all we know.

Firs of all: I don’t have calendar in my URL (?) and the URLs as quite short; for example: http://www.dennisknickel.com/event/viewster

Thanks in advance!

https://wordpress.org/plugins/the-events-calendar/