If your Dotdigital account is not functioning correctly, you could ask your administrator to allow the below IP ranges.
Email sending ranges Europe (region 1)
94.143.105.1 - 94.143.105.255
94.143.106.1 - 94.143.106.255
94.143.107.1 - 94.143.107.255
94.143.108.1 - 94.143.108.255
Email sending ranges North America (region 2)
212.1.218.1 – 212.1.218.255
212.1.219.1 – 212.1.219.255
Email sending ranges Asia Pacific (region 3)
212.1.222.1 - 212.1.222.255
212.1.223.1 - 212.1.223.255
Here are some further IPs that may also need to be considered.
External dynamic content & emailsim for Europe (region 1)
52.174.92.164
20.54.90.19
20.54.93.233
20.54.94.18
20.54.92.62
51.124.11.55
51.124.14.184
51.124.75.156
51.124.76.105
External dynamic content & emailsim for North America (region 2)
104.208.235.109
20.75.40.163
20.75.42.223
20.75.42.225
20.75.42.202
20.80.121.219
20.80.121.248
20.80.121.251
20.80.121.253
External dynamic content & emailsim for Asia Pacific (region 3)
104.210.118.87
20.53.120.175
20.53.121.40
20.53.122.178
20.53.124.79
52.243.70.174
13.77.44.160
52.243.66.251
52.243.65.25
SMS for all regions
52.155.162.26
51.105.196.109
Webhooks for all regions
20.93.237.19
20.93.235.124
20.93.236.168
20.93.235.223
20.93.236.1
20.93.236.191
20.93.235.117
20.93.237.48
20.93.236.137
20.93.237.12
20.105.10.168
20.105.10.159
20.105.10.95
20.105.9.192
20.105.10.110
20.105.10.6
20.105.10.127
20.105.10.151
20.105.9.194
20.105.10.99
52.142.82.109
40.74.1.247
Dynamics CRM connector for Europe (region 1)
23.101.50.109
23.102.11.18
23.102.18.218
40.85.101.127
40.127.207.8
168.61.83.197
Dynamics CRM connector for North America (region 2)
13.68.20.229
13.68.22.210
13.68.30.243
20.190.237.249
40.79.40.67
40.84.63.147
Dynamics CRM connector for Asia Pacific (region 3)
52.237.219.144
52.237.242.56
52.237.243.40
52.237.243.42
104.210.65.149
Salesforce connector for Europe (region 1)
40.69.43.141
40.127.143.93
52.169.177.10
52.169.188.52
Salesforce connector for North America (region 2)
13.68.21.184
40.84.2.30
40.84.3.8
40.84.7.130
Salesforce connector for Asia Pacific (region 3)
52.237.218.85
52.237.222.198
52.237.240.76
52.237.242.158
These IP addresses are also used by emailsim. To learn more, check out http://emailsim.io/.
WooCommerce connector (all regions)
Europe (region 1)
35.158.29.16
North America (region 2)
18.220.204.55
Asia Pacific (region 3)
13.55.107.246