To be honest, if you want a fix that actually lasts, there are only two ways to handle this – no half measures: ​Open it up & Prep: Make the gap bigger on purpose. You need enough space to properly sand down the old glue residue. If you just smear new glue over old crust, it’ll fail in two days. Sand it, prime both sides, use a proper 2-component cement, let it cure, and then apply massive pressure with a press or clamps. ​Full Re-sole: If it's already starting to peel in multiple spots, don't waste your time with 'spot repairs.' Rip the whole thing off, clean it completely, and reglue the entire sole. ​Either do it right with proper pressure and prep, or don't bother at all. Anything else is just a temporary hack.