I got this:
Arduino: 1.8.9 (Windows 10), Board: "WeMos D1 R1, 80 MHz, Flash, 4M (1M SPIFFS), v2 Lower Memory, Disabled, None, Only Sketch, 921600"
sketch\Calandar.ino.cpp.o: In function `_GLOBAL__sub_I_host':
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:251: undefined reference to `HTTPSRedirect::HTTPSRedirect(int)'
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:251: undefined reference to `HTTPSRedirect::~HTTPSRedirect()'
sketch\Calandar.ino.cpp.o: In function `connectToWifi()':
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:70: undefined reference to `HTTPSRedirect::HTTPSRedirect(int)'
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:77: undefined reference to `HTTPSRedirect::~HTTPSRedirect()'
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:84: undefined reference to `HTTPSRedirect::getData(String&, char const*, char const*)'
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:88: undefined reference to `HTTPSRedirect::HTTPSRedirect(int)'
sketch\Calandar.ino.cpp.o: In function `getCalendar()':
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:105: undefined reference to `HTTPSRedirect::getData(String&, char const*, char const*)'
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:112: undefined reference to `HTTPSRedirect::~HTTPSRedirect()'
sketch\Calandar.ino.cpp.o: In function `setup':
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:209: undefined reference to `HTTPSRedirect::HTTPSRedirect(int)'
sketch\Calandar.ino.cpp.o: In function `createEvent(String)':
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:123: undefined reference to `HTTPSRedirect::getData(String&, char const*, char const*)'
C:\Users\plipp\Documents\Arduino\Calandar/Calandar.ino:125: undefined reference to `HTTPSRedirect::~HTTPSRedirect()'
collect2.exe: error: ld returned 1 exit status
exit status 1
Error compiling for board WeMos D1 R1.
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.