Since Steempress is working for me, I highly suspect you might have done something wrong without noticing anything.

1. Check if your Connectivity to the Steem Server shows OK
2. Check if you might have checked some boxes on categories that Steempress will ignore that will prevent Steempress to publish the content on Steem.

3. Check if you might have set the Delay option too long. Bear in mind that this are all in minutes not seconds. So a 300 value would be the same as publishing it after 5 hours.

If all else fails, try asking for help in their Discord Server: https://discord.gg/YSa8TFW