If you halt sending for a period of time, it is recommended that you re-warm your dedicated sending domain before you go back to your normal sending cadence. Inbox providers like to see consistency (in both volume and engagement), and if they notice that a specific sender resumes sending after a while, they will potentially flag that sender as suspicious. Note that you don’t need to go through the whole warm up process again. Starting off with a 30 days engaged segment will work!  

For additional resources on how to warm up your sending domain, you can check out the Guide to Warming Your Sending Infrastructure article.