You do know that these Olba feeders are being dumped on the U.S. market because of design problems? You can buy pallets of them super cheap, Google Olba and their link will pop up. They are pretty feeders but the clogging is well known and one of the chief complaints in their horde of Amazon negative reviews.
https://www.amazon.com/Automatic-Tr...e=avp_only_reviews&sortBy=recent&pageNumber=1
18 negative, 53 positive reviews but that is counting the initial compensated reviews where people got a free or reduced price feeders in return for posting a review. I think Amazon has banned the incentivized reviews practice now. I'd bet money that Amazon won't take long to ban the sale of the feeder as they are very protective of their customers and a 34% negative review rate is going to eventually get their attention.
I'd try waxing the interior of the feeder once a week using bee wax, not car wax or floor wax. Dump the feed out, rub the wax in really well and leave it alone for a bit, then give it a good polishing with a soft rag and re fill the feeder. Woodworking shops use wax on the saws and shaper tables to reduce friction without contaminating the wood surface with silicone or oils.Usually in a normal feeder the pellets will flow easier than the crumbles. If the waxing doesn't fix the problem you might see if there is some way to open up the "throat" or the choke point at the bottom of the feed bin. Maybe take out a dime size hole and test it for a few days. The vibration from the door opening and closing will affect the flow rate so be conservative and wait a few days before cutting another hole or making the first one larger. But first consider if opening up the throat might create problems with the small lower eating area. This feeder isn't like a normal treadle feeder that has a large area to store the feed that has dropped down.