I had my first migration and it failed (sort of) - the application crashed and was unavailable, and was also impossible to delete.

I tried another migration, with the same result - but by the time the second migration was completed, the first one suddenly started working!

The support agent was just as confused as I was. He did mention this problem occurs sometimes.

I suggest to include a small "please allow 5 minutes after migration for server synchronization". This could save a lot of support time and frustration (After the second migration failed I was ready to throw in the towel.)