The "timeout" error message means your PHP scripts are not communicating with Maxima. The most likely cause is that you have an incomplete upgrade. You will need to
(1) go to the plugin page and choose the direct connection (not "optimised" and not "server").
(2) run the healthcheck script.
If the healthcheck script runs fine, then create an optimised image. If not, email me privately and let me know the errors from the healthcheck. I suggest you don't post your configuration details here.
Chris