I mean, the sentence itself doesn't seem all that bad IMHO, it's the context that makes the difference. If I'm in a real time conversation actively trying to fix the issue, saying "oof, so sorry about this" seems like a perfectly genuine way of expressing the mutual feeling of frustration.

Writing this same sentence with an emoji beside it on a customer support documentation page, however, looks quite unprofessional. In these types of contexts, the general writing etiquette is that one is expected to write using a less casual tone.