@BarryBL The problem still persists with accepting friend invites here https://accounts.codemasters.com/account/update
I can confirm the same issue as reported by @Samuel Dodee, @Chipwich, @Sidshaw et al. It is not related to any specific game but it is a racenet issue.
I have tried to accept the Friend Request(s) from different PCs running different OSes (Win10, Win7, Manjaro Linux) and also from different browsers (Chrome, IE, Brave with shields down). My friends have the same issue on their side with accepting a friend request from me.
On top of this issue - probably related - you cannot remove any exiting friends either. On the friends management tab if I click "Remove" on one of my existing friends I get the following:
One common thing in all my own tests are that the accounts are/were linked to our Steam accounts if this helps? I did try to unlink my Steam account from racenet but get the same error when I try to accept a friend request.
Keeping fingers crossed you can fix this bug. It is a show stopper for a number of people.
Cheers