Zoho Mail doesn't work with VPN

Zoho Mail doesn't work with VPN

Hello, 

Could you help me with the next question, please!?

Once I try connecting to the VPN service (Hola VPN), Zoho Mail become inactive. Everything works fine without the VPN software. Is this issue related to the VPN service or Zoho Mail? Which VPNs work with Zoho best? Do solutions reviewed here can resolve my issue? Should I take advantage of paid options to guarantee good work with Zoho Mail?

Thanks in advdnce!