Problem statement: Open rates for a new customer via Journey builder tool has gone down after a good start for the initial 2 months and it needs to be rectified. This campaign is for good/reliable customers and not external leads/prospects
Details: We have initiated the IP warming for a new Org with around 100,000+ emails via Journey builder[with incremental approach] and it had a good open rate of upwards of 20%. It went for a duration of 5-6 weeks. Post that we initiated real Journey for our customers and the open rates were encouraging for the first 2 months i.e upwards of 30%. Emails sends were 200,000+ for the first month[in 3 shots]. But post-second month onwards, the open rates went down even though the emails send was around 100,000.
Any ideas as to what went wrong from the SFMC perspective? And how to correct it to increase the open rates?