Likely, more information is needed to properly answer. You could, however, add the site you are trying to access to the SSL Pass Through list in the Burp proxy options. This has the consequence of losing the ability to inspect request and response in Burp, but it will let you access the site while still using the burp proxy. You can read more about Burp's SSL Pass Through feature here:

PortSwigger Web Security Blog - SSL Pass Through

Perhaps you could provide any output you receive from Burp's Alerts tab for a more accurate answer.

Likely, more information is needed to properly answer. You could, however, add the site you are trying to access to the SSL Pass Through list in the Burp proxy options. This has the consequence of losing the ability to inspect request and response in Burp, but it will let you access the site while still using the burp proxy. You can read more about Burp's SSL Pass Through feature here:

PortSwigger Web Security Blog - SSL Pass Through

The SSL Pass Through options can be found under the Proxy > Options tab.

Based on your Alerts tab output, you may have to further alter the SSL settings in Burp under the Options > SSL tab. You can try enabling protocols and ciphers that are not currently enabled, or changing the options in the SSL Negotiation Workarounds section.