You initialise a string with nothing text_3 = ""
which throws an error in psychopy 2020.2.5. when running online. Initliase your string with a space or some dummy text
text_3 = "."
or text_3 = "dummy"
or text_3 = " "
or upgarde to the current version 2020.2.8. This error has been fixed in the meantime.