Why can't I open HTML files

[Android Central Question]

I have bn able to open them up until now. Message says invalid parameter. I have tried downloading HTLM reader, but receive same message. TY for your assistance

 

[ManiacJoe]

Where are these files located?
Locally on the phone? On the internet?
Can any of your web browser apps open them?

Which phone?
Which version of android?
Which carrier?
Which apps are you trying to use?