Polar - Unable to link your account

When I’m trying to add my Polar Flow account on the Synced Devices page, I repeatedly get the message

“Unexpectedly unable to link your account.
Maybe Polar is having a bad day?”

If I deliberately use a false password, I correctly get

“Unable to login with the Polar email and password you set. Have you recently changed your email or password on Polar’s website?”

so a wrong username/password does not seem to be cause.

Tested in Firefox 52 on Suse Linux.

Hi @gernot.g, I saw that you were able to import your latest run through Polar. Was the issue intermittent, or did it turn out to be a credentials problem with an incorrect error message?

@chris It seems to be intermittent. I tried it again today and it just worked, same procedure, same credentials.

Before submitting the first report I had tried unsuccessfully twice with a few days in between.