Instead of men and women working together in harmony, they are competing against each other. My answer is about western countries. I can't speak for asia and africa.

1. Feminists don't support MRAs and MRAs don't support feminism.
2. Women infiltrate male spaces to turn them into female spaces. Men don't trust women who enter male spaces.
3. Men don't want to work for a female boss.
4. Women agree with affirmative action to bring more women into STEM and leadership positions, and men don't agree with affirmative action.
5. The sexual revolution has created more incel males and more women who are single for years. More sexual agency and choice has caused more men and women to be single over a long period.
6. Despite women getting more freedoms, women's happiness is decreasing while men's stays the same or is increasing.
7. Society is trying to make men more feminine and women more masculine, so we can't tell who is masculine and feminine anymore so everyone is the same identity.
8. Men don't want to get married any more and marriage rates are decreasing.
9. Anxiety and depression rates are increasing amongst teenagers despite more gender equality, better health, less poverty, less disease, more culture and more technological advancements.
10. Men are scared to approach women for fear of being called or seen as creepy or being criticised for sexual harassment.
11. 51% of British people haven't had sex in the previous month, along with 50.2% of American people. These figures are set to rise every year.

Sources

https://www.theguardian.com/lifeandstyle/2015/aug/06/fewer-than-half-uk-adults-satisfied-sex-lives-charity-research-relate
http://archive.is/CrT1u