I assumed the issue is on your site as on infinityfree 2 big domains are offered for subdomains
There is 2 more offered by infinityfree but less common while behind subdomains are offered by byet.org so to avoid NX Domain Finished Error every domain have a CNAME records of * points towards some promotional ads domain and every register domain have an A records pointing towards to an IP!
Means like your domain points toward javiersouza.epizy.com > 22.214.171.124
While an invalid domain will points towards
*.epizy.com allies of 11776.BODIS.com
which means if an invalid domain like iufbwiyfeb.epizy.com will redirects you to 11776.BODIS.com thus this maybe your DNS resolver fault that your subdomains dosen’t resolve correctly thus I recommend you to use 126.96.36.199 service by Cloudflare for DNS resolve https://everykhas.tk/2018/04/boost-your-internet-speed-with.html
Above are the results tested on