it is due to bad cable, or connectors.
The easy fix is get a managed switch, and set up the ports to Auto-negotiation, Speed: 1000, Duplex Mode: Full
It will running as 1gbps, but due to the bad cable quality, it will only run 200mbps-Max, depends on how bad the cable is, and how much the noise it.
sample configuration on Netgear GC510P
the issue is due to MX record lost some how after shared mailbox created.
e.g. my personal domain shin.li, MX record check
flags QR RD RA
shin.li. IN MX
shin.li. 21599 IN CNAME shinli.com.
shinli.com. 14399 IN MX 0 shinli-com.mail.protection.outlook.com.
go to Microsoft domain page, https://admin.microsoft.com/AdminPortal/Home#/Domains
found out all records are missing.
re add all required record to DNS server, and it will fix the issue
vmware fusion is disappeared in Screen Record part, can’t add it.
it is due to vmware fusion 11.5.x not support on new MAC OS
please install vmware fusion 11.0 and it will fix the issue