Hello,
Please follow the instructions in this documentation to activate debug in your site to see any PHP errors recorded that can provide insight on to whats going on. Please reply with a link to debug.log file. If you are not able to do this please send us FTP access to your site so we can do this for you.
Could you also give us full access:

Hello Thomas,
I am not sure what is going on. Your WP_DEBUG did not receive any errors. But I am seeing 503 server errors.

I wonder if it would be possible for your disable other plugin and switch to default WP theme and see if this error stil happen?
Hi Faisal,
can u please let us know exactly what is not working?
Ashan,
the receipt came to dev@thrivepop.com
The problem is that neither I nor they can find the add-on among their purchases.
Thank you for your messages, I am going to assign this ticket to Ashan and he will be able to take it from here and find you a solution. Please allow some time for him to get back to you, we greatly appreciate your patience and thank you for being a eventon customer!

Thank you! I didn’t realize I could download the add-on plugin from my account. I did so and installed it and it’s working. One last question (tried searching for this but nothing came up…): Is there a way to start the week with Sunday? Most calendar views (Apple, etc.) list Sun-Sat so having the days shifted is confusing. I appreciate your help.
I have refunded your order Casey. If you have more questions, kindly send us a new ticket and we would be more than happy to help you resolve your issues!
please send your email address
Sorry for the delay in getting in here. What is your order ID or email used to purchase? with out that I can not look up the order that was charged.
ALso what day (exactly) did you receive reminder email and what day was the order charged ?
Hello,
This is not safe. Removing these lines can affect the overall work of the entire plugin.
Please also check this guide: https://docs.myeventon.com/documentations/why-my-site-and-eventon-page-loading-slow/