Custom Codes Support Query for Codrop Theme

Good Day

I downloaded a theme from Envato (Codrop theme) earlier this year.
Following the development and launch of our website, we aimed to link the website to
their AdWords account.

We are having difficulty inserting the “Event Snippet” for their AdWords conversion tracking
code to the website. I tried using the “Custom Codes” element to install the snippet directly
on the page as well as a standard text block, however when I do it won’t allow me to update
or save the page. When I refresh the page, the code I added is then removed.

The AdWords campaign setup is directing to the, the Global site tag
in the header but the event snippet cannot be added to the Thank You page I created

Kindly advise at your earliest convenience as to a solution for the above as we require the
Event Snippet on the Thank You page in order to effectively track conversions.

Should you have any queries, please do not hesitate to contact me.