Click continue. It just means that the webpage is encrypted and your information is encrypted, but your actual internet connection is NOT encrypted, so it is possible for someone to get your encrypted info. However, it is extremely difficult to crack the encryption, so don't worry about it.
Short answer, don't worry about it. Your info is encrypted so it is secure and you are protected. Go ahead and click Continue.
The webpage has assets that originate from a 3rd party, which are not encrypted.
This is a normal condition, and USUALLY not a big deal, but there are potential risks.
It helps to turn off 3rd party cookies. Look in browser> Tools> Options> Privacy.