I am subscribed to about four or five forums with the subscription setting to daily updates (via email). Until recently this worked sweet and interestingly it continues to work sweet for the individual thread subscriptions (immediate notifications). However for some reason the forum subscription email no longer comes through.
I have tried marking all forums read; looked for cookies to reset within the forum but nothing found and tried unsubscribing and re-subscribing. None of which has helped.
BTW it works okay at other forums such as MTBR which also uses vBulletin forum software but a later version.
Tech have tested and nobody else seems to be reporting the issue... possibly it is local to you or your ISP.
That does not sound logical given (1) emails advising updates of individual threads come through (e.g., how I was aware of your reply) and (2) it works fine with other forums including forums using the same software.