550 5.7.708: Microsoft 365 will not accept traffic from your sending IP
550 5.7.708 blocks mail from low-reputation IPs, and trial tenants are the usual case. What Microsoft documents for it, 5.7.705, 5.7.750 and 5.7.703.
550 5.7.708 blocks mail from low-reputation IPs, and trial tenants are the usual case. What Microsoft documents for it, 5.7.705, 5.7.750 and 5.7.703.