Hey @Howard,
I’m sorry to hear about this – when you enter your license key, does the license key “stick” in the license key field? Or does the license key vanish from the field when you click “Save Changes”.
Also, I noticed in your system information that Events Calendar Pro is at version 3.12.6 on your site, which is out of date. If possible, update Events Calendar Pro form inside your wp-admin if there is an “Update” button for it on the Plugins page.
If not, then at this time I would recommend just manually updating Events Calendar Pro to 4.0.2 and seeing if anything improves here – you can find the files for a manual update like this by heading to http://theeventscalendar.com/my-account/downloads
Cheers,
George