Lately, there is only one solve button, associated with griddler puzzles. It is the touch screen Solve button, as there is no + sign available. On griddlers that are 30 or more squares, it makes it impossible to solve them.

I"m using a Mac, with Big Sur 11.5.1 The two Solve buttons were there last week.

I have tried two different browsers, restarted the browsers, and the computer, but can't get the "computer" Solve button back.

Any suggestions?

There is griddlers list under menu Puzzles->Griddlers and there you have to click Details button on the puzzle. On that detail page you can see two solve  buttons.
Rasto