Hello, Marianne! Welcome to planDisney and thanks for your question!
Did you
purchase your tickets on the Disneyland Resort website? If so, it is very likely that you made your
theme park reservation at the time of purchase. When buying tickets online, you select the date you want to visit and which park you want to visit that day. That is your theme park reservation--no extra steps required. And that is probably why you are getting the error that the ticket has reached its limit. You can double check the theme park reservations you have in place by clicking the "Ticket and Reservation Details" link under the "My Disneyland" menu on the Disneyland Resort website.
In preparation for your trip, you'll want to read up on the new
Disney Genie service that is debuting soon. Disney Genie is a complimentary digital feature in the Disneyland app that will create customized park-touring strategies based on your interests. You will also have the option of purchasing Disney Genie+ for $20 per day, per ticket. With Disney Genie+, you will select the next available return time for an attraction and then skip most of the wait by using the Lightning Lane. Since you have already purchased your theme park tickets, you will be able to add on Disney Genie+ in the Disneyland app each day that you are in the parks.
I hope your visit to the Disneyland Resort is full of magic and memories!
-Linda