This should fix it:

1.
Press the 3 stripes button in the top right corner. Press on history and go to clear browsing data. Then check every box and press clear browing data at the bottom.

2. Find your flash settings. If you are on windows 8 just open the search from the upper right corner and search for "flash player" and click on the setting buttons, should show up now. Open it and go to "delete all", once in there check the first box and press delete at the bottom.

After this your client should surely work again