Uploading to mega shows as 'MALFORMED_ATTRIBUTES' on mega cloud.

[ghost]

Uploading some files gives me that. What characters aren't allowed when uploading to mega or uploading in general? Also why is uploading to mega so slow? Upload speed is pretty decent (300Mbps) but it takes a lot of time (i assume it has to do with these chunks, the more there are the more it takes?):

chunk 897/947: offset: 935854080, length: 1048576
chunk 898/947: offset: 936902656, length: 1048576
chunk 899/947: offset: 937951232, length: 1048576
chunk 900/947: offset: 938999808, length: 1048576
chunk 901/947: offset: 940048384, length: 1048576
chunk 902/947: offset: 941096960, length: 1048576
chunk 903/947: offset: 942145536, length: 1048576
chunk 904/947: offset: 943194112, length: 1048576
chunk 905/947: offset: 944242688, length: 1048576
chunk 906/947: offset: 945291264, length: 1048576
chunk 907/947: offset: 946339840, length: 1048576
chunk 908/947: offset: 947388416, length: 1048576
chunk 909/947: offset: 948436992, length: 1048576
chunk 910/947: offset: 949485568, length: 1048576
chunk 911/947: offset: 950534144, length: 1048576
chunk 912/947: offset: 951582720, length: 1048576
chunk 913/947: offset: 952631296, length: 1048576
chunk 914/947: offset: 953679872, length: 1048576
chunk 915/947: offset: 954728448, length: 1048576

[ghost]

So it looks as if nothing besides letters, numbers, spaces and dots is allowed.