What should I do if migration is blocked by autopkgtest failing on a dependency?

[Joachim Zobel <jz-2017@heute-morgen.de>]

Hi.

A package I just uploaded [1] is blocked. Are there any guidelines on
what I am expected to do? Should I create a bug for the blocking
package?  

Sincerely,
Joachim

[1] https://qa.debian.org/excuses.php?package=mosquitto