Between April-August BCB probably tried quite a bit. They wanted to arrange a series with SL not sure why that never happened. And in the monsoon season Bangladesh isn't suitable for hosting cricket matches so some team had to host us really. Zimbabwe was a good option but they had a series with India and a test match with NZ.
Also, the window was open for a series with India in India. We were told about a 3 match ODI series and a solitary test but India backed out which they should have done much earlier so BCB could have discussed matters earlier. You can't really arrange a series within a short time given the climate and global terrorism issue.