There are Time of Day Guards for importing fields, which will limit when and if you can add a new field both when importing a dataset or via Edit database fields. If you have more records than the below limits then you will not be able to add a new field to your campaign.
- 08:30:00 - 10:00:00 > 250,000 records
- 10:00:01 - 18:00:00 > 120,000 records
- 18:00:01 - 21:00:00 > 250,000 records
For example, if you have 500,000 records in Campaign1 and try to add a new field at 9:00 a.m. GMT you will not be able to do so (the limit is 250,000 records). However, this will be possible after 21:00 p.m. GMT (the limit has been lifted). If you have less than the above number of records in your campaign between the specified times you will be able to add fields at will, likewise for newly created Campaigns.
Currently, the US platform for ContactNow uses the above UK time of day guards as well. This means that at 21:00 GMT or 13:00 PTZ the guard will lift for San Jose, for example. This is under review to be changed to a more convenient time zone for US customers.