I have >7 yrs experience in healthcare, telecom, financial institution, start up & the government sector. Would the universities I went to derail my application? (they are not top unis)

I have an MBA and MSc in Data Science from AIB and University of Aberdeen. I am also certified in CHE,PMP, Lean Black Belt and AI Practitioner.  I thought I had great experience but got rejected even after a referral. 

1. Would the universities I went to deter my application?

2.How many pages should my resume be? And should I include all of my certifications.

is there anything that I could do or change that should help support my application?

Thank you!