Can't log into CM500 modem

Hello.  I've been having a lot of trouble over the past 6 months with my internet constantly buffering and it's gotten worse since January.  I've called Comcast over and over, and finally someone came yesterday.  He wouldn't check the modem since I own it, but we cheacked everything else.  I decided to check the logs today because the issue came back.  I can't log into my account.  In fact, once I type in my password, it looks like the page is loading, but it just sits there.  I know it's not my connection because every other page loads.  What could be going on?  I've only had this modem for two years.  I'm using High Sierra and I *think* the firmware is updated  (V1.01.08).  Thanks bunches.

(If I can get in and look at the logs, should I delete them?  I'm always hesitant to get rid of data.)