2 type issue This site can’t be reached ERR_NAME_NOT_RESOLVED issue

Our website me and my clients facing same issue, but our clients different country and different internet connection but getting error https://snipboard.io/oacCuV.jpg see this primary domain not working but one subdomain working all other not but my other customer all not working ,some of other customer another subdomain working so very confused and my pc i already done all troubleshooting steps , cmd clear,reset all comands done tried different browser but same but at the same time another my office pc another sub domain working its very strainge pleas check
2 type issue = ERR_NAME_NOT_RESOLVED , err_quic_protocol_error

What are the domain names? They are obfuscated in your screenshot.

this domain some of them working some devices like that but this hosted one 2 different server via cloudways they said no issue at all

and this post dont show google search that why i dint share domain names becuase last happen this , please remove this post from cloudflare sitemap