Can't upload saved photos to online gallery

I use Lightroom mobile on my desktop (not classic) to edit all my photos and recently have had issues with saving photos. They save to both my Mac and external hard drive just fine, but when I go to upload it to an online gallery to send to my clients (I use pixieset) they say error or are unable to download. I always save as jpeg and have tried small, large size and custom sizing. Sometimes it will upload like 4 or 5 photos and not the rest. And it's not a space issue with pixieset because I have deleted and tried uploading other photos. I tried a free trial of pic-time but it did the same thing. SOS please and thank you in advance because I need to get some galleries out this weekend!