In some cases this can be related to not having boundary and discovery methods configured. In others, DNS resolution to the client may not be working. In a case I worked recently, it was due to AV exclusions not being in place. This client runs Windows Defender, and they had not enabled management through ConfigMgr like they thought they had. Once we did this and put AV exclusions in place listed on Microsoft's AV Exclusion Reference for ConfigMgr, the client push installation worked like a charm. This was with vanilla, unmanaged Defender on Server 2019 with no exclusions applied (aka stock). I suspect the setting causing it was Configure monitoring for incoming and outgoing file and program activity not being set to scan incoming files only.