If nothing happens when you click Create Event or Update Event, the cause is usually your monthly event limit or a field that needs fixing. Work through these checks.
Check your monthly event limit
If the Create Event and Create Draft Event buttons are greyed out, you have used your plan's events for this month. A banner at the top of the page says so and shows when it resets, for example Your monthly limit resets on followed by the date.
The Free plan includes 10 events a month. The month runs from the day of the month your team was created, not from the 1st. Premium and Business have unlimited events. See Free plan limits for how the count works.
A recurring series that will not fit in what you have left is refused, with a message showing how many events it needs. Shorten the series or upgrade.
Look for a highlighted field
When something on the form needs fixing, AddCal opens the section that holds it and scrolls to the first message. Fix the field shown in red and click Create Event or Update Event again.
The Location field is limited to 2,048 characters. If you pasted a very long link or address, you see a message under the field. Shorten it, or put the extra detail in the description.
"Unable to verify captcha" on the AddCal homepage
The event form in your dashboard has no captcha. The message Unable to verify captcha. Please try again. only comes from the homepage form for creating an event without an account, which runs a bot check.
Ad blockers, Brave Shields, privacy extensions and VPNs can stop that check. Turn them off or open the page in a private window, then try again. Signing up for a free account avoids the check. For more on the check, see Stuck on "verifying your browser".
Still stuck
Try a private window with extensions turned off. If it still fails, contact support with your browser name and a screenshot of the whole form.