500 Server Error occurs several times a day

EVERY DAY(!), 2-3 times during the day, I encounter a problem with the following symptoms:

  1. I can’t log into the game, the game says Steam Connection Required. Ofc, Steam is running, I’m logged in to it, and everything works fine in it.
  2. I click on the My Account link in the upper right corner(on this page, for example) >> Click the LOGIN WITH STEAM button >> page appears on steamcommunity.com site and offering me Sign into portal.lastepoch.com using your Steam account, the correct data of my Steam account is shown below and I click the Sign In button >> I get a white page with the inscription 500 Server Error in the center.

Obviously, the root of both problems is the same - LE<–>Steam communications. From the Steam side, I don’t see a single sign of any kind of malfunction, absolutely everything is working (store/community/account details/ect.). And of course I CAN log-in to other games purchased in Steam. Again, error 500 is not issued by the steamcommunity website, but by the portal.lastepoch website. The error lasts for 15-60 minutes and then “repairs” (herself?). After fixing, both problems above disappear(I can play/I can log-in in My Account), BUT! Only until the next 500 error, which is 2-3 per day, EVERY day(!). Ideas?