Error: Unexpected : in add_header Alt-Svc line

I am trying to reload NGINX version 1.31.7 but I get the following error:

nginx: [emerg] unexpected ":" in /etc/nginx/sites-enabled/try.ictmee.nl:49

Line 49 of the linked sites-available file corresponds to:

add_header Alt-Svc 'h3=":443"; ma=86400' always;

I have seen this line in online searches but it always has the : in it. So I don’t understand where this error could be coming from.

Any ideas?

I have resolved this issue. There was an error in pasting a line a few lines earlyer.