We all know about the ERR_SPDY_PROTOCOL_ERROR that only affects the Google Chrome Internet browser. It always shows This webpage is not available. Chrome users can’t access certain websites affected by this error. To solve this follow the steps:-
1. Launch Chrome browser.
2. On the corner click on three dots.
3. Go to More Tools > Clear Browsing Data
4. Click on the Clear Data.
After performing such steps the history from the chrome browser cache is cleared. But in case if you are unable to do so than visit Fix Err Spdy Protocol Error Not Responding. All the guidelines are helpful.